Circles Test Circumference/Area Calculator Active Clearly label the following in the circle to the right. 1. Point B as the center 2. Diameter AC 3. Radius BD 4. Chord EF 5. Arc FG Find the following. Show all work. Round each answer to the tenths place and use 3.14 for pi when necessary. 5. A circle has a radius of 12 inches. Find: a) The diameter of the circle b) The circumference of the circle c) The area of the circle 6. A circle has a diameter of 1.8 kilometers. Find: a) The radius of the circle b) The circumference of the circle c) The area of the circle
Choose the correct answer for each of the following problems. Show all work. Use 3.14 for pi. 7. What expression would you use to find the area of a circle with a diameter of 24? a. 3.14(24)(24) b. 3.14(24) c. 3.14(12)(12) d. 3.14(12) 8. What expression would you use to find the area of a circle with a radius of 2? a. 3.14(2)(2) b. 3.14(1)(1) c. 3.14(2) d. 3.14(1) 9. Tom wants to cover the top of a circular table with material. The diameter of the table is 18 inches. How many square inches of material are needed? a. 254.34 in. 2 b. 56.52 in. 2 c. 1,017.36 in. 2 d. 508.68 in. 2 10. What is the circumference of this circle? a) 45.3416 cm. b) 181.3664 cm. c) 23.864 cm. d) 11.932 cm. 7.6 cm. 11. The circumference of a circle is 10.99 inches. What is the diameter of the circle? a. 1.75 in. b. 3.5 in. c. 7 in. d. 5.495 in.
Solve each problem. Round answers to the tenths place and use 3.14 for pi. Show all work. 12. Joe s cow is tied to a post with a piece of rope that is 15 feet long. What is the area in which the cow can graze? 13. A round game table has a diameter of 1 m. How much plastic laminate is needed to cover the top of the table? 14. The diameter of the earth at the equator is about 8,000 mi. Based on this figure, how far is it around the earth? 15. Radio Station KROQ broadcasts in all directions to a distance of 40 miles. How many square miles are in the station s broadcast area? 16. World Record: The world s largest Ferris Wheel was built in London in 1897. The wheel had a radius of 150 feet. How far would you travel in one turn of this wheel?
Student Answer Sheet Circles Test Circumference/Area Clearly label the following in the circle to the right. 1. Point B as the center 2. Diameter AC 3. Radius BD 4. Chord EF Find the following. Show all work. Round each answer to the tenths place and use 3.14 for pi when necessary. 5a. Diameter = 5b. Circumference = 5c. Area =
6a. Radius = 6b. Circumference = 6c. Area = Choose the correct answer for each of the following problems. Show all work. Use 3.14 for pi. 7. 8. 9. Answer Answer Answer
10. 11. Answer Answer Solve each problem. Round answers to the tenths place and use 3.14 for pi. Show all work.
12. 13. 14. Answer Answer Answer 15. 16. Answer Answer
Answer Key Circles Test Circumference/Area Clearly label the following in the circle to the right. Check circle for each of the following. 1. Point in center labeled B 2. Line segment AC going all the way across the circle and passing through the center point 3. Line segment BD going from the center to the outside of the circle 4. Line segment EF having both endpoints on the circle. Find the following. Show all work. Round each answer to the tenths place and use 3.14 for pi when necessary. 5a. Diameter = 24 in. 5b. Circumference = 75.4 in. 5c. Area = 452.2 in. 2 diameter = radius(2) 12(2) C = pi(diameter) 3.14(24) 75.36 A = pi(r 2 ) 3.14(12 2 ) 452.16
6a. Radius = 0.9 km. 6b. Circumference = 5.7 km. 6c. Area = 2.5 km. 2 radius = diameter/2 1.8/2 0.9 C = pi(diameter) 3.14(1.8) 5.652 A = pi(r 2 ) 3.14(0.9 2 ) 2.5434 Choose the correct answer for each of the following problems. Show all work. Use 3.14 for pi. 7. If d = 24, then r = 12. 3.14(12 2 ) or 3.14(12)(12) 8. 3.14(2 2 ) or 3.14(2)(2) 9. If d = 18, then r = 9. 3.14(9 2 ) 254.34 C Answer A Answer A Answer
10. 11. d = 7.6 C = pi(d) 3.14(7.6) 23.864 C = pi(diameter) 10.99 = 3.14(d) 10.99/3.14 = d d = 3.5 C Answer B Answer Solve each problem. Round answers to the tenths place and use 3.14 for pi. Show all work.
12. r = 15 3.14(15 2 ) 706.5 13. If d = 1, then r = 0.5. 3.14(0.5 2 ) 0.785 14. C = pi(d) 3.14(8000) 25,120 706.5 ft. 2 Answer 0.8 m. 2 Answer 25,120 mi. Answer 15. r = 40 16. If r = 150, then d = 300. 3.14(40 2 ) 5,024 C = pi(d) 3.14(300) 942 5,024 mi. 2 Answer 942 ft. Answer