1. Circles

2. 2 Circle: Plane figure Not a polygon Not made up of line segments

3. Diameter: Longest chord, line, in a circle 3

4. Radius Line segment with one endpoint at the center of the circle and the other endpoint on the circle. Half of the Diameter 4

5. Area: A = r 5

6. Find the area 6 77 cm

7. Find the area 7 12 m

8. Find the area 8 24 cm

9. Find the area 9 56 ft

10. Circumference: Distance around a circle C = d C = 2 r 10

11. Find the circumference 11 77 cm

12. Find the circumference 12 12 m

13. Find the circumference 13 24 cm

14. Find the circumference 14 56 ft

15. All About Words 15

16. Word Problems A circular shield has a diameter of 20 inches. Find the area of the steel needed to cover one side of the shield. 16

17. Word Problems A pizza recipe calls for the dough to be rolled out to form a circle with a diameter of 18 inches. Find the area of the dough when it is rolled out. 17

18. Word Problems The diameter of a circle that a shot- putter stands in is 7 feet. What is the area of the circle? 18

19. Word Problems Meteor Crater in central Arizona was formed when an asteroid struck Earth between 20,000 and 50,000 years ago. The circular crater has a diameter of 1.2 kilometers. Find the area of the crater to the nearest hundredth. 19

20. Word Problems An architect is making a plan for a new circular theater. The diameter of the theater is 32 meters. What is the circumference? 20

21. Word Problems A builder is putting in a circular window. What is the circumference if the diameter is 4 feet? 21

22. Word Problems A builder is putting in a circular window. What is the circumference if the radius is 2 feet? 22

23. Word Problems A gardener is digging a circular pond. If the diameter of the pond is 5 yards. What is the circumference? 23

24. Word Problems The first Hula Hoop was introduced in 1958. What is the circumference of a Hula Hoop with a 3 foot diameter? 24

25. Word Problems The circumference of a circle is 24 meters. Find the diameter. 25

26. Word Problems Stan needs a new bicycle tire. His tire has a circumference of about 113.04 inches. What is the diameter of the tire? 26

27. Word Problems Billy Bob needs a new Hula Hoop. His Hula Hoop has a circumference of about 42.39 feet. What is the diameter of the Hula Hoop? 27

28. Word Problems The circumference of a circle is 4 What is the area? Leave your answer in terms of pi. 28