10.7 Area of Circles and SectorsBrett SolbergAHS‘11-’12

Warm-up 1) What is the circumference of the circle?

Find the Arc Length Arc length =

2) Arc AB

3) Arc BC

What HW questions do you have?

Today’s Agenda pi Area

circle activity to discover

sector segment

Quiz retakes Test on Tuesday CRT – 9 classes

Pi ratio of circumference and diameter of a

circle

d*π = c

π ≈ 3.1415926525

Area of A Circle

What is the radius of: rectangle parallelogram triangle trapezoid

What do these all have in common? What is the formula for circumference? Haw is the radius and diameter related?

Area of a Circle

A = b*h

Area of a Circle A = π r2

Area Examples Find the area if:

r = 3

r = 10

d = 14

Pizza Sizes

Pizza Sizes

10” 12” 14” 16” 23”

Area in π

Area in decimal

Sector A sector of a circle is a region enclosed

by a central angle and an arc.

Area of a Sector Area = Area of circle *

Example 3 Find the area of a sector with a radius of

6 and a central angle of 100˚.

Example 4 Find the area of sector ZOM in terms of

π.

Segment Region bounded by an arc and a line

connecting the endpoints of the arc.

Area of a Segment

area of a sector

area of an isosceles triangle

area of a segment

Example 5 Find the area of the shaded segment in terms

of π, and then round to the nearest tenth.

Example 6 Find the area of the segments and the

square.

10 in

Assignment 10-7 WS EC Review pg 592 #1 – 20 all EC Activity pg 575

Due Next Class 10.1-10.7 Worksheets Chapter 1-10 Cumulative Review Warm-ups