Areas of circles, sectors and segments of circles

1
Areas of circles, sectors and segments of circles

• 5.8

2
Theorem 5.12

• The Area of a circle is the product of and
  the square of the radius.
• A r2

r
3

• Segment of a circle the part of a circle
  bounded by an arc and a segment joining its
  endpoints

Segment of a Circle
4

• Find area of sector ZOM

• Area of Sector ZOM
• mZM/360 x r2
• 72/360 x (20)2
• 80

z
72o
20
m
o
5
Find area of segment Z

• Area of sector area of triangle area of
  segment
• Sector
• mAB/360 x r2
• 90/360 x (10)2
• 1/4 x 100 25
• Triangle
• ½ (10)(10) 50
• Area of Segment
• 25 - 50 or about 28.53

a
z
b
o
10
6
Homework

• P 288 1-21, 24-27