1. Warm UP!
Circle O has a radius of 20 feet. What is the length of arc KL? K
65o O L
20 ft

2. Homework
Questions?

3. Area of
6.8
Circles & Sectors

4. The amount of space inside a circle.
Area of a Circle
The amount of space inside a circle. r
A= pr2

5. Find the area.
53 cm
7.6 yd
181.5 square yards
square cm
A= pr2

6. Practice 11.5B
#s 1-7

7. A = pr2 C = 2pr A = p  52 10p = 2pr A = p  25 5 = r A = 78.54 in2
Example 1
If S has a circumference of 10p inches, find the area of the circle to the nearest hundredth.
A = pr2
C = 2pr
A = p  52
10p = 2pr
A = p  25
5 = r
A = in2

8. Find the area of the shaded region.
Example 2
Find the area of the shaded region.
A = p22
A = p  82
A = p  4
A = p  64
2 in
A = in2
A = in2
6 in
A shaded = A – A= =
188.49in2

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

10. Area of a Sector
WHY?

11. How Do You Find the Area
of a Circular Sector?

12. Find the area of the sector.
Example 3
Find the area of the sector. R
6 cm 60 Q
A  cm2

13. Find the area of the sector.
Example 4
Find the area of the sector.
6 cm
120
7 cm Q R
A  cm2

14. Practice 11.5B
#s 8-10

15. Circumference and
Arc Length in Circles

16. Homework Unit 10 Test Review Show ALL Work for Credit!!
Study for Thursday’s Test over 6.7 and 6.8