1. CHAPTER 10.1 CIRCLES AND CIRCUMFERENCE

2. A circle is the set of all points in plane equidistant from a given point called the center of the circle CIRCLES

3. CONCEPT

4. EXAMPLE 1 Identify Segments in a Circle A. Name the circle and identify a radius.

5. EXAMPLE 1 Identify Segments in a Circle B. Identify a chord and a diameter of the circle.

6. EXAMPLE 1 A. Name the circle and identify a radius. A. B. C. D.

7. EXAMPLE 1 B. Which segment is not a chord? A. B. C. D.

8. CONCEPT

9. EXAMPLE 2 Find Radius and Diameter Answer: QV = 10.5 cm If RT = 21 cm, what is the length of QV? RT is a diameter and QV is a radius.

10. EXAMPLE 2 A.12 cm B.13 cm C.16 cm D.26 cm If QS = 26 cm, what is the length of RV?

11. CONCEPT

12. EXAMPLE 3 Find Measures in Intersecting Circles

13. EXAMPLE 3 A.3 in. B.5 in. C.7 in. D.9 in.

14. CONCEPT

15. EXAMPLE 4 Find Circumference CROP CIRCLES A series of crop circles was discovered in Alberta, Canada, on September 4, 1999. The largest of the three circles had a radius of 30 feet. Find its circumference. Answer: The circumference of the crop circle is 60  feet or about 188.50 feet.

16. EXAMPLE 4 A.377.0 feet B.392.5 feet C.408.3 feet D.422.1 feet The Unisphere is a giant steel globe that sits in Flushing Meadows-Corona Park in Queens, New York. It has a diameter of 120 feet. Find its circumference.

17. EXAMPLE 5 Find Diameter and Radius Find the diameter and the radius of a circle to the nearest hundredth if the circumference of the circle is 65.4 feet.

18. EXAMPLE 5 A.8.4 m B.5.35 m C.2.67 m D.16.8 m Find the radius of a circle to the nearest hundredth if its circumference is 16.8 meters.

19. EXAMPLE 6 Circumference of Circumscribed Polygon

20. EXAMPLE 6 A. B. C. D.