SB En Geom 10­7 Completed.notebook
November 29, 2012
Lesson 10­7
Areas of Circles and Sectors
Thm 10­11
Area of a Circle
A = πr2
Expl 1.
How much more pizza is in a 12 in. diameter pizza than in a 10 in. pizza?
Ckpt 1. How much more pizza is in a 14 in. pizza than in a 12 in?
Nov 19­7:18 PM
sector of a circle ­ region bounded by an arc of the circle and the two radii to the arc's endpoints
Thm 10­12 Area of a Sector of a Circle
Area of a sector = mAB x πr2
360
Z
Expl 2. Find the area of sector ZOM.
Leave your answer in π.
20cm
72
M
O
Ckpt 2. A circle has a diameter of 20 cm. What is the area of a sector bounded by a 208 degree major arc? Round your answer to the nearest tenth.
Nov 19­7:21 PM
1
SB En Geom 10­7 Completed.notebook
November 29, 2012
segment of a circle ­ part of a circle bounded by an arc and the segment (chord) joining its endpoints
look in you book for pictures
A
Expl 3. Find the area of the shaded region.
Round your answer to tenths. O 10 in
B
Nov 19­7:26 PM
Ckpt 3. A circle has a radius of 12 cm. Find the area of the smaller segment of the circle determined by a 60 degree arc. Round your answer to the nearest tenth.
Nov 19­7:29 PM
2
SB En Geom 10­7 Completed.notebook
November 29, 2012
Extra 2. Find the area of sector ACB. Leave your answer in terms of π.
C
6m 100 o
B
A
Extra 3. Find the area of the shaded segment. Round your answer to the nearest tenth.
A
B
120 o
24 ft
O
Dec 10­1:08 PM
homework
lesson 10­7
2­28e, 35­37
41,42
Nov 19­7:30 PM
3