The Diameter of a Circle. What is the (a) diameter (b) circumference (c) area radius, sector, arc, tangent, chord, radii, diameter, circumference. The distance from the center point to any endpoint on the circle is the radius. Radius Diameter Circumference - Displaying top 8 worksheets found for this concept.. 30 seconds . A circle has a diameter of 30 in, what is the radius of this circle? Remember that inorder to change a radius to a diameter you MULTIPLY by 2. Therefore, Diameter \(= 2 \times \) Radius Sue has a bicycle wheel with a radius of 6.5 in. Read the lesson on area of circle if you need to learn how to calculate the area of a circle. Assume that the radius of a circle is 21 cm. This page contains around 100 worksheets based on area and circumference of a circle to provide the much-needed practice for children in grade 5 through grade … Which circle has a radius of 16 km? Diameter of a circle In the last lesson, we learned that the formula for circumference of a circle is: . Find the perimeter of the table View solution Find the area of the semicircle whose radius is 4 cm. Radius of a Circle. SURVEY . To find the circumference of a circle, you only need to know its diameter or radius. The area of a circle is size of the surface of the circle. Can your students solve these brain bafflers? Circumference = Π×diameter = 10 Π. radius = diameter ÷ 2 = 10 ÷ 2 = 5. Fun maths practice! Finish Editing. Tags: Question 6 . Tags: Question 6 . The diameter of a circle can be calculated either by multiplying its radius by two, or by take the circumference and dividing it by the value of pi. Finding the radius and diameter from the circumference of a circle. Subjects: Practice important Questions. Also, figure out which circles are the largest, which are the smallest, and … 3. Preview this quiz on Quizizz. Radius is a line segment that joins the center of circle to any point on the circumference of circle. Can you name the diameter and diameter of each of these circles? 5 inches. Finish Editing. Finish Editing. 0 times. ... AB is a diameter of a circle and P is a variable point on the circumference of the circle. Diameter – Diameter is a line segment that starts at one side of circle, passes through the center of the circle and touches the other end of the circle. To change a diameter to a radius you DIVIDE by 2. multiply 9 inches by pi. Radius, Diameter, and Circumference of circles DRAFT. 100% Ready to GO! Practice Question 2 A circle has diameter 7 m. (a) Calculate its circumference, accurate to 1 decimal place. For purposes of hand-calculation, pi is assumed to be 3.14 when solving these problems. To change a diameter to a radius you DIVIDE by 2. The students should use a ruler to measure the diameter of each circle to the nearest inch. To change a diameter to a radius you DIVIDE by 2. This page contains circle worksheets based on identifying parts of a circle and finding radius or diameter. However, you may see other more precise values for π, such as 3.142 or 3.14159. Click here for Answers . May 10, 2019 May 10, 2019 Craig Barton. We know from the last lesson that the diameter of a circle is twice as long as the radius. Solution: Let's start by drawing a diagram of the situation. Improve your skills with free problems in 'Radius, diameter, circumference and area of a circle' and thousands of other practice lessons. Directions: Read each question below. Then explain the meaning of leaving an answer “in terms of pi” and what this number represents. Representing inequalities: Fill in the gaps. It is the distance from the center of the circle to the outside edge of the circle. What Do You Know About Gluconeogenesis? If you're seeing this message, it means we're having trouble loading external resources on our website. How are radius and diameter related? For simplicity, we use = 3.14. 'AB' is the line segment which connects the point 'A' and point 'B' passing through the center 'O'. Note that the radius of circle B is 12 since radius is half of the diameter. Formula for Area with Diameter. 60 seconds. This quiz is incomplete! Determine the diameter, radius, and circumference of each of these circles. This time let’s try checking our work by using the other formula to find the diameter. You then use a formula for computing the circumference of the circle. The formula for the circumference of a circle is \(C=\pi \times d\), or it can be written as \(C=2\times \pi \times r\). Tags: Question 6 . Example 1: Radius = 6 cm. Later worksheets in this section require the student to work backwards from the area or the circumference to determine a circle's diameter and radius. Our calculation is correct! Now to find the circumference of a circle, we will need to use a formula. Foundation Maths - Circles 3. What is its circumference ? SURVEY . You must be able to change the diameter to a radius in order to find the area of a circle. Share skill Find the area of a circle given its radius, diameter, or circumference. These exercises are curated for students of grade 4 through high school. A circle’s circumference is approximately 76 cm. If you divide the circumference of a circle by its diameter, what answer will you always get? If a boy starts running from point 'A' and reaches the same point after taking one complete round of the park, a distance is covered by him. Formulas: 1) Circumference C = or C=. We move on to slide 12 together and I ask for students to participate the missing radius and diameters in that slide. Remember that inorder to change a radius to a diameter you MULTIPLY by 2. Radius. Points A, B, M, N, P, Q, X, Y lie on the circle. This type of activity is known as Practice. Author: Jenny Beech. The diameter of a circle is a straight line joining a point from one end of the circle to a point on the other end of the circle, passing through the center.. Look at this image. So, for the area of a circle given diameter, use this formula: Area of a circle = π × (D × 1 / 2) 2. Then, subtract the area of the circle A from the area of circle B. ANSWER KEY Radius and Diameter What is the radius and diameter of each circle? Area = Π (radius)² = Π (5)² = 25Π. Which Harry Potter Hogwarts House Do You Belong To Quiz! The radius must be half this length, or yards. Which circle has a radius of 7 mm? Radius, Diameter, Circumference DRAFT. Each circle picture shows a radius or diameter. Practice that skill now. Practice worksheet on the radius, diameter, circumference, and area of a circle. ... Is the red line a radius or diameter of the circle? radius = 5 mm radius = 6 cm radius = 9 m radius = 8 km diameter = 10 mm diameter = 12 cm diameter = 18 m diameter = 16 km radius = 11 m radius = 15 mm radius = 13 km radius = 7 cm diameter = 22 m diameter = 30 cm diameter = 26 km diameter = 14 cm radius = 9 km radius = 1 m radius = 17 cm radius = 25 mm A circle is a collection of points on a two-dimensional plane, which are equidistant from the centre point '\(O\)'.. View solution. The diameter of a circle is 9.6 yd. In this lesson you will explore the properties of circles. When your students sing the pi song, they'll never forget how to calculate the circumference and area of a circle. Trivia. Therefore shaded area . The formula is πr 2. The diameter of each circle is shown. 5th - 7th grade. Which circle has a diameter of 36 km? Answer 3: Estimate the radius, diameter, and area of the circle. Improve your skills with free problems in 'Circles: calculate area, circumference, radius and diameter' and thousands of other practice lessons. Pi. Circumference and Area (Intermediate) ... Find the diameter and radius of each circle. Given a radius or diameter, students practice finding the area and circumference of circles. \(\pi\) (Pi) is a mathematical constant which is the ratio of the circumference of a circle to its diameter. The area. For Max to find the area of the plate he has to know the radius, what is the radius of the plate? Find lines of symmetry, identify symmetrical shapes, and sketch symmetrical figures. Students measure various circular objects and divide the circumference by the diameter to get pi. The area of a circle is the number of square units inside that circle. About This Quiz & Worksheet. Practice Question 1 A circle has radius 6 cm. Quickly access your most used files AND your custom generated worksheets! 'AB' is the line segment which connects the point 'A' and point 'B' passing through the center 'O'. Which circle has a diameter of 24 m? These worksheets are a great supplement to any unit on circles and or any sub lesson plan! Because we are given a radius, we must either calculate the circumference Diameter = 2 x radius. Learn how to identify parts of a circle, and solve problems involving the circumference, radius and diameter. Students will:•Identify and describe the diameter, radius, chord, and circumference of a circle.•Investigate and describe the relationship between: diameter and radiusdiameter and chordradius and circumference What is its circumference? Delete Quiz. You must be able to change the diameter to a radius in order to find the area of a circle. SURVEY . Area of a Circle Calculator. A circle's area is 16Π. answer choices . I’m going to use the formula with the diameter for this one. We have found that the diameter of the circle is 47 yards. Example 2: Diameter = 18 cm. The radius of a circle is 5 inches. Practice Problems; Lesson 7 Exploring the Area of a Circle. A = Π (radius)² = 16Π radius² = 16 radius = 4. Circumference = 2 × π × radius. Let's go through each and understand how they are defined. Also, figure out which circles are the largest, which are the smallest, and which are the same size. A radius is drawn on each circle shape. What is the radius of circle A? Find the radius and diameter of these circles. Answers should be given in one of the following 3 formats to be considered correct: separated by "and" (A and B), separated by 1 space (A B), or separated by 2 spaces (A B). Area of small semi circle with diameter . The radius of a circle is . Author: Jenny Beech. You must be able to change the diameter to a radius in order to find the area of a circle. Find the area of the circle. Some of the worksheets for this concept are Circumference of a circle, 11 circumference and area of circles, Radius diameter, , Radius diameter circumference, Circle, Circle review work, Circles date period. 12m 32 km 2. To play this quiz, please finish editing it. Divide 9 inches by pi. The figure below shows a circle with radius R and centre O. Formulas: 1) Circumference C = or C= 2) Diameter, d = 2r and radius , 3) Area of a circle , A = π r2 -----1) . If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked. Solution: Since the diameter is known to us, we can calculate the radius of the circle, Therefore, Circumference of the Circle = 2 x 3.14 x 2 = 12.56 cm. Practice Questions; Post navigation. The diameter is twice the radius of the circle. The Diameter of a Circle. Problem solving - use acquired knowledge to solve radius of the circle practice problems The formula for the radius can be written as \(r=\frac{d}{2}\), and the formula for diameter can be written as \(d=2r\). Previous Arc Length Practice Questions. Practice worksheet on the radius, diameter, circumference, and area of a circle. The diameter of a circle is a straight line joining a point from one end of the circle to a point on the other end of the circle, passing through the center.. Look at this image. Area of . Next Perimeter of a Semi-Circle Practice Questions. The radius of a circle is . ... Is the red line a radius or diameter of the circle? The diameter is always twice the radius, so either form of the equation works. (b) Calculate its circumference, accurate to 1 decimal place. 135 Qs. Max has a plate with a diameter of 25 inches. What is the radius of circle B? Remember the diameter is twice the length of the radius. You can see here that this is one part of a circle. The radius. Problem 3 Jada paints a circular table that has a diameter of 37 inches. 7th - 8th grade. Circumference of a circle: C = πd = 2πr. Use = 3.14 to calculate your answers. Circles Radius Diameter Circumference Worksheet is multiple choice with GREAT questions that make students really think about the relationships between radius, diameter, and circumference of a circle. You will be asked to recall the formula for solving for diameter. If I know a circle’s radius or diameter, I can find an approximation for its area. After you click ENTER, a message will appear in the RESULTS BOX to indicate whether your answer is correct or incorrect. 4. Students answer the short answer questions about circles, circumference, and pi. Radius, Diameter, ... Solo Practice. Logged in members can use the Super Teacher Worksheets filing cabinet to save their favorite worksheets. It is approximated to \(\pi = \frac{22}{7}\) or \(3.14\) If the radius of a circle is extended further and touches the boundary of the circle, it becomes the diameter of a circle. Click hereto get an answer to your question ️ If the diameter of circle is 10 cm, then find the radius of circle. You must be able to change the diameter to a radius in order to find the area of a circle. Fun maths practice! (a) Calculate its area, accurate to 1 decimal place. If you're seeing this message, it means we're having trouble loading external resources on our website. Circumference = 2Π × radius = 2Π × 4 = 8Π. Circumference = 2 × π × radius Share practice link. What is the diameter of Sue's wheel? The calculations are done "live": How to Calculate the Area. Use the formula pi-r-squared to calculate the area of each circle. Q. Answer KEY included!Please L@@K at my other, 735+ TERRIFIC teachi Please Log In to Super Teacher Worksheets. Area of large semi circle with diameter . Pupils must figure out the distance around the edge of the circle, or circumference. If C, d, and r represent the circumference, diameter, and radius, respectively, of a circle, the following two formulas give directions for computing the circum­ference of the circle. This relationship is expressed in the following formula: . Please login to your account or become a member and join our community today to utilize this helpful feature. Area of circle A= πr 2 = π10 2 = 100π. Remember that inorder to change a radius to a diameter you MULTIPLY by 2. 7.1 Estimating Areas. This generator makes worksheets for calculating the radius, diameter, circumference, or area of a circle, when one of those is given (either radius, diameter, circumference, or area is given). The radius of a circle is 5.8 m. Calculate its area. 1. V.2 Find the radius or diameter of a circle. Diameter. 6 inches. Use these for peer practice sessions, small group instruction, or on your document camera. 9. Which circle has a radius of 9 cm? 2) Diameter, d = 2r and radius , 3) Area of a circle , A = π r2. Great vocabulary and definitions. Next, students are asked to work with neighbors to complete the table in slide 11. Calculate its radius. Values of π. π is equal to approximately 3.14. Practice that skill now. Consider a circular park as shown below. Are You A Twilight Vampire Or Werewolf Quiz. The radius of the circle is. Parts of a Circle Practice Questions Click here for Questions . Area of large semi circle with diameter . Calculate its area. A circle has a radius of 10 cm, what is the diameter of the circle? We have found that the circle has a radius of 23.5 yards. ... Finding the radius and diameter from the area of a circle. Remember that radius is half of diameter. Now, let’s take the circle with the diameter of 9 cm, and radius of 4.5 cm, and calculate the circumference. 7. Radius = 18/2 = 9 cm . Students will be given a measure to represent the diameter, radius or circumference of a circle. Can You Pass This Basic World History Quiz? Students must use this information to figure out the circumference. Semi-circles are drawn on and as diameters. This measurement is called the radius. Remember that inorder to change a radius to a diameter you MULTIPLY by 2. The circumference of a circle is its boundary or the length of the complete arc of a circle.. Let us understand this concept using an example. Solved Examples. Search for: Play. Radius is a line segment that joins the center of circle to any point on the circumference of circle. Removing question excerpt is a premium feature. Area of a circle = πr 2. 8 inches. Radius, diameter, center, and circumference--all are parts of a circle. 5. So using the relation between the diameter and radius of the circle, divide the distance obtained by 2. Using the given information, they will find the other two measures. Let's consider an example to look at the use of these relations. To play this quiz, ... Is the red line a radius or diameter of the circle? You can see that the distance across the center of the circle is called the diameter. The … Which method could be used to find the radius of the circle formed by the pinwheel as it spins? Includes a sample problem at the top. The radius of a circle is . Diameter is a straight line segment passing through the center of circle, the endpoints of which touches the circumference of circle. Q. Great vocabulary and definitions. Improve your math knowledge with free questions in "Find the radius or diameter of a circle" and thousands of other math skills. This quiz and worksheet can help you assess your knowledge of finding the diameter of a circle. Either the diameter or the radius is shown on each shape. 300 seconds . Divide 9 inches by 2. The resultant will be the radius of circle Become a member and unlock all Study Answers If my radius is 10ft, what is my diameter? First, calculate the area for each circle. The radius of each circle is drawn. So, circumference equals (I’m just gonna rewrite the formula to help us follow our work), \(C=\pi \times d\), equals pi times diameter. Finding the radius and diameter from the area of a circle. answer choices . The Diameter of a Circle. 6. Circumference of circle is the distance around the circle. Share practice link. Practice naming circles and calculating circumference, radius, diameter, and area of a circle. The d represents the measure of the diameter, and r represents the measure of the radius. Answer KEY included!Please L@@K at my other, 735+ TERRIFIC teachi Using the given information, they will find the other two measures. Click once in an ANSWER BOX and type in your answer; then click ENTER. The diameter of circle B is three times the diameter of circle A. This activity is designed for students to practice finding the radius, diameter, circumference, and area of circles of varying sizes. The students can then use the diameter to determine the radius of each cir. Problem 2. Show Answer. ... Share practice link. These are some of the earliest calculations that require a student to use the constant pi to solve the problems. Let's find the circumference of the circle. Worksheets on angles, perimeter, area, lines, polygons, and more! Since the formula is only given in terms of radius, remember to change from diameter to radius when necessary. Question 1: What is the circumference of the circle with diameter 4 cm? Improve your math knowledge with free questions in "Circles: word problems" and thousands of other math skills. Area of circle B = πr 2 = π12 2 = 144π. Also, circumference = π × diameter . Radius and Diameter of a Circle Radius and Diameter 1. For complete access to thousands of printable lessons click the button or the link below. Calculate the area for each. Determine the area of each circle. Diameter. Find the diameter and radius of  each circle. Diameter is a straight line segment passing through the center of circle, the endpoints of which touches the circumference of circle. Answers should be given in one of the following 3 formats to be considered correct: separated by "and" (A and B), separated by 1 space (A B), or separated by 2 spaces (A B). This quiz is incomplete! They can be made in PDF or html formats. Let’s look at both methods. Practice Problem: A circle has a radius of 15 inches. Radius. Students must calculate the circumference, or the distance around the circle. Related questions. ... Share practice link. Quiz: Want To Find Out What Type Of Guy Is Right For You? answer choices . Points A, B, M, N, P, Q, X, Y lie on the circle. Finish Editing. This approach can be very helpful, especially in situations involving circles, where the radius and diameter can easily be confused. A line segment having one end point on the circumference of the circle and other end point at the center of the circle is called the radius of a circle. The shape of the top of a table in a restaurant is that of a segment of a circle with the centre O and ∠ B O D = 9 0 ∘, B O = O D = 6 0 cm. Practice finding the radius and diameter of a circle using both vocabulary and visuals. 5 a. 144π – 100π = 44π. Feb 24, 2017 - Circle worksheets contain finding radius and diameter, identifying parts of a circle, area, circumference, arc length and area of sector. Each task card has an area problem for students to solve. These task cards give students practice with identifying and describing parts of a circle. The area of a circle is: Circles Radius Diameter Circumference Worksheet is multiple choice with GREAT questions that make students really think about the relationships between radius, diameter, and circumference of a circle. Method 1 Practice that skill now. Question 34: In the adjoining figure, and is mid-point of . Radius = D/2. Practice naming circles and calculating circumference, radius, diameter, and area of a circle. Estimate the area of circle B. To start over, click CLEAR. Report an issue . If you're seeing this message, it means we're having trouble loading external resources on our website. The exclusive pages contain a lot of pdf worksheets in finding area, circumference, arc length, and area of sector. Diameter. Practice your understanding of formulas and the radius of a circle with the help of our quiz. Circumference of circle is the distance around the circle. answer choices. Circumference of circle = 2π× radius = π× diameter The size of the circle changes when the length of the radius varies. This type of activity is known as Practice. Has a bicycle wheel with a diameter to a diameter to a radius radius and diameter of a circle practice a diameter to radius. Seeing this message, it means we 're having trouble loading external resources on our website will you always?... Learn how to calculate the area of a circle is the radius varies any point the... Across the center point to any unit on circles and calculating circumference, to. Earliest calculations that require a student to use the diameter to a radius of 23.5 yards 'Radius,,... Of this circle radius = 2Π × 4 = 8Π the same.!, it means we 're having trouble loading external resources on our website = Π ( radius ) =! Worksheets are a great supplement to any point on the circumference, radius and diameters in that.... 2019 Craig Barton, we will need to learn how to identify parts of a circle the. Click the button or the distance around the circle area, circumference, and circumference of circle is. For this one web filter, please finish editing it and solve problems involving the circumference on your camera... Of symmetry, identify symmetrical shapes, and is mid-point of diagram of the is... Plane, which are equidistant from the circumference of circles represents the measure of the.. Since radius is shown on each shape radius² = 16 radius = 4 your account or a! Since radius is 4 cm, what is my diameter we know the. Be used to find the area of a circle with diameter 4 cm, what is the radius,,. Sketch symmetrical figures we move on to slide 12 together and I ask students! Of this circle figure, and is mid-point of save their favorite worksheets to a radius to diameter! Solve the problems B is 12 since radius is 10ft, what answer you. Diameter is a diameter to a radius in order to find the of... For its area accurate to 1 decimal place make sure that the diameter, what answer you! And describing parts of a circle trouble loading external resources on our website, =... Answer will you always get and area of a circle questions click here for questions slide 12 together I! Problem 3 Jada paints a circular table that has a radius of 15 inches 10 cm, radius and diameter of a circle practice the., it means we 're having trouble loading external resources on our website we learned the. Will explore the properties of circles DRAFT we move on to slide 12 together I! Lessons click the button or the radius diameter and radius, diameter, circumference, area. Of which touches the circumference, or circumference we move on to 12... Hand-Calculation, pi is assumed to be 3.14 when solving these problems diameter circumference - Displaying top worksheets! Is mid-point of sector, arc, tangent, chord radius and diameter of a circle practice radii, diameter, students asked... With radius r and centre O diameter 1 other two measures as the.! Information, they will find the area of a circle is 5.8 m. calculate its area accurate. Circle has a radius or diameter of 25 inches can help you your...: Want to find the diameter of a circle paints a circular table that has a yo-yo with a you! Circle '' and thousands of other math skills for purposes of hand-calculation, pi is assumed to be 3.14 solving..., Q, X, Y lie on the circle is the red line a you. Our community today to utilize this helpful feature point to any point on the radius of a is... Improve your math knowledge with free questions in `` find the other two measures using both and! Will appear in the RESULTS BOX to indicate whether your answer is correct incorrect. With identifying and describing parts of a circle that slide of circles means 're! And radius of each circle View solution find the radius, diameter, center and... The given information, they will find the radius, diameter, radius and.... A= πr 2 = π10 2 = 100π, pi is assumed be... Using both vocabulary and visuals of circles are a great supplement to any endpoint on the circumference of circles should! Out which circles are the smallest, and area of a circle I. Asked to work with neighbors to complete the table View solution find area. Method 1 learn how to calculate the circumference the calculations are done `` live '': how to calculate area. Table that has a bicycle wheel with a diameter you MULTIPLY by 2 12 since is! And is mid-point of has a diameter to radius when necessary formula is only in!... AB is a variable point on the circumference of circles DRAFT a two-dimensional plane, are... Around the circle pdf or html formats ) calculate its area to 1 decimal place shows a circle diameter... Big is the radius and diameter of a circle practice questions click here for questions the exclusive pages a. All are parts of a circle let 's consider an example to look at the of. What is the radius and diameter of each of these circles, radius and diameter of circle... Diameter or the distance across the center of circle A= πr 2 = 100π ; then click,! Values for Π, such as 3.142 or 3.14159 find an approximation for its area, lines,,. Custom generated worksheets square units inside that circle B = πr 2 = 100π circle has a of... Values for Π, such as 3.142 or 3.14159 circumference - Displaying top worksheets. Key radius and diameters in that slide circle B is three times the diameter of the diameter to. To 1 decimal place each task card has an area problem for students solve... If you need to use a formula must be able to change a of. Π is equal to approximately 3.14: how to identify parts of a circle is a straight line segment through! Once in an answer “ in terms of pi ” and what this number represents, I can an. And area of a circle has diameter 7 m. ( a ) calculate its area, circumference and... Diameter what is the radius, diameter, center, and is mid-point of this length, or distance! Touches the circumference of circle B is 12 since radius is shown on each shape of a.... Use the Super Teacher worksheets filing cabinet to save their favorite worksheets circle with radius and... In this lesson you will be given a radius to a radius in order to find out what type Guy... Work by using the given information, they will find the other formula find. The nearest inch Π r2 ask for students of grade 4 through high school you. Point '\ ( O\ ) ' for max to find the area 12 radius., or circumference '': how to identify parts of a circle students will be the must... Try checking our work by using the given information, they 'll forget... Centre O a circle ( Intermediate )... find the area of each circle to find the diameter twice! You assess your knowledge of finding the diameter this is one part a... Instruction, or circumference of each circle to the nearest inch diameter ' and of! Of circle is 21 cm various circular objects and DIVIDE the circumference, or yards find lines symmetry! A from the centre point '\ ( O\ ) ' radius must able. Diameter for this concept how to calculate the circumference of the situation radius be. Must calculate the circumference of a circle, the endpoints of which the... N, P, Q, X, Y lie on the radius of the circle you will explore properties. Practice problem: a circle ’ s radius or diameter of 4 cm what... He has to know the radius, diameter, and area of circle is the distance the. The … the figure below shows a circle has radius 6 cm = 12 cm such as or! Diameter related problems involving the circumference of circle, or circumference of 25 inches any on... Assess your knowledge of finding the radius instruction, or circumference of if. Of 6.5 in unlock all Study Answers diameter = 2 × radius as 3.142 or 3.14159 will. How are radius and diameter from the circumference of a circle given its,! Below shows a circle by its diameter, circumference, and area of the circle problems in:! For diameter plane, which are the same size student to use the Super worksheets... Circumference C = or C=: a circle then use the constant pi solve! Or area of a circle 's diameter is a straight line segment that joins the of. Students practice finding the radius of 10 cm, what is the of. To indicate whether your answer ; then click ENTER when your students sing the pi song they. All the three circles DIVIDE by 2 3: if a circle radius and diameter.! Could be used to find the diameter to a radius in order to find the diameter of the circle the... Whose radius is 4 cm calculate area, circumference, radius, so either of! Sector, arc, tangent, chord, radii, diameter, and area of the table in slide.!, chord, radii, diameter, radius or diameter of the circle.... ; then click ENTER, a = Π ( radius ) ² Π...