Daily Homework Quiz For use after Lesson 10.2

Find the area of the circle given its radius r. Use 3.14 for π.

1. r = 20 in. ANSWER

A = r2

A = 3.14 x 202

A= 1256 in.2

If we were given area, how could we find the radius?

If the Area of the circle is 200.96 sq ft.

Find the radius: A = r2 200.96 = 3.14 x r2

3.14 3.14 64 = r2

√64 = √ r2

8 = r

Given the Area- Find the Radius

Steps:1. Take the Area and divide by 3.14

- This is the radius squared.2. Take the square root. - You now have the radius of the

circle.

If the Area of the circle is 615.44 sq in.

Find the radius: A = r2 615.44 = 3.14 x r2

3.14 3.14 196 = r2

√196 = √ r2

14 = r

Find the area of the green shaded region

10 in

25 in

Rectangle: A= 10 x 25 = 250

Circle: A = 3.14 x 25= 78.5

78.5 x 2 = 157

The green area: 250 – 157 = 93

480.42m2

Homework

P. 529 #16-18, 33-34.

ROUND TO THE NEAREST TENTH!!!!!!

SHOW YOUR WORK!