Unit 9 – Day 4 Homework Assignment1. Read through and take notes from the

following slides

2. Write down any questions you have while reading

– Things you don’t understand– Definitions that sound confusing– etc

3. Write down and attempt to solve each example problem

– Leave yourself room to show work

Arc Length and Sector Area7-7 and 7-8

Today’s Objective

› Students will be able to calculate the length of an arc and the area of a sector.

7-6 Arc Length

› Review: The Circumference is the distance around a circle. – C=2πr or C=πd

› Definition: The Arc Length is the distance around an arc (a fraction of the circumference)

› Arc length is DIFFERENT from Arc Measure****

Arc Length: is a fraction of a circle’s circumference (in terms of pi)

Arc Measure: is equal to the central angle (in terms of degrees)

Example

› Find the LENGTH of arc AB

Ex 2: Find the length of arc ADB

Example 4

› The area of a circle is 100 cm2. Find the length of an arc of 75o

7-7 Sector Area

› Review: The Area of a circle is π*r2

› Definition: A Sector is a region bounded by an arc and two radii

› The area of the sector is 75π cm and AB = 10 cm. What is the measure of <CAB?

C

A

B

Segment of a Circle

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

Area of a Segment

Finding the Area of a Segment of a Circle

Ex 1: Find the area of the segment:

Ex 2:

Example: Find the area of the shaded region

12cm

Challenge Find the area of the green figure.

Bring Questions to Class

› QUIZ TOMORROW!