1. Areas of Plane Figures 11-6 Arc Lengths and Areas of Sectors
11-7 Ratios of Areas
A ____________ of a circle is a region bounded by two radii and an arc of the circle.

2. Length of
In general, if :
Length of
Area of sector

3. Example 1 Find the length of and the area of the shaded sector. A 45°B 8

4. Example 2
Find the length of and the area of the shaded sector. A 3 B

5. Example 3 Find the length of and the area of the shaded sector. A B 10
30°

6. Example 4
Find the length of and the area of the shaded sector. A 6 B

7. Theorem 11-7 If the scale factor of two similar figures is a : b, then
(1)
(2)

8. Example 5
Find the ratio of the perimeters and the ratio of the areas of the two similar figures. 6 15
CW: p ; p
HW: p even, 24-26