1. 7-2 Sectors of Circles
Objective: To find the arc length of a sector of a circle and to solve problems involving apparent size.

2. Sectors of Circles
A sector of a circle, shaded below, it is the region bounded by a central angle and the intercepted arc.

3. Sectors of Circles
Example 1: The radius of a pizza is 6 cm. mROQ = 60o. Find the area of the slice OQR. R
6 cm
60° O Q

4. Sectors of Circles
Example 2: The radius of a cake is 7 cm. If the area of sector ROP is cm^2. Find the central angle of the sector OPR. R
7 cm O P

5. Arc Length and Area of a Sector of a Circle
In general, the following formulas for the arc length s and area K of a sector with central angle  .
If  is in degrees, then the arc length and the area of a sector is:
If  is in radians, then the arc length and the area of a sector is:

6. Example 3: A sector of a circle has an area of 30 square inches and central angle 3π/4 radians. Find its arc length.

7. Homework
Textbook Pg. 265 #14