McGraw Hill Integrated II, 2012
MH
McGraw Hill Integrated II, 2012 View details
1. Graphing Quadratic Functions
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Exercise 76 Page 103

Recall the formula for the area of a circle.

G

Practice makes perfect

Let's start by using the formula for circle area to solve for the radius.

A = π r^2
36π = π r^2
36 = r^2
±6 = r
r = ± 6

Since r represents a unit of length, we can ignore the negative solution. When we double a radius of 6, we get 12. Now, we can find the area of a circle with r=12.

A = π r^2
A = π ( 12)^2
A = 144 π