1. 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 = π r2
A = 3.14 x 202
A= 1256 in.2
If we were given area, how could we
find the radius?

2. If the Area of the circle is 200.96 sq ft.
Find the radius:
A = π r2
200.96 = 3.14 x r2
3.14 3.14
64 = r2
√64 = √ r2
8=r

3. 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.

4. If the Area of the circle is 615.44 sq in.
Find the radius:
A = π r2
615.44 = 3.14 x r2
3.14 3.14
196 = r2
√196 = √ r2
14 = r

5. 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

6. 480.42m2

7. Homework
P. 529 #16-18, 33-34.
ROUND TO THE NEAREST TENTH!!!!!!
SHOW YOUR WORK!