1. Warm-Up 1.Find the circumference of a circle with a diameter of 10ft. Round your answer to the nearest tenth. 2.Find the circumference of  A if the radius is 2.5. Round your answer to the nearest hundredth. 3.Find the radius of a circle with a circumference of 56.5 m. 31.4 ft 15.71 8.99 m

2. Area The amount of space occupied. r A=  r 2

3. Find the area.

4. Example 1 If  S has a circumference of 10  inches, find the area of the circle to the nearest hundredth. C = 2  r 10  = 2  r 5 = r A =  r 2 A =  5 2 A =  25 A =  in 2

5. Example 2 Find the area of the shaded region. 188.49 in 2 6 in 2 in A =  2 2 A =  8 2 A =  4 A = 12.57  in 2 A =  64 A = 201.06  in 2 A shaded = A – A= 201.06 - 12.57 =

6. Sector the region bounded by two radii of the circle and their intercepted arc.

7. Area of a Sector

8. Example 3 Find the area of the sector. A  18.85 cm 2 60° 6 cm Q R

9. Example 4 Find the area of the sector. A  51.31 cm 2 6 cm 120º 7 cm Q R

10. Example 5 Find the radius if the area of the sector is 96.8. r  10 6 cm r cm Q R A = 96.8 mArc = 110º