### Home > CC2 > Chapter 9 > Lesson 9.1.2 > Problem 9-31

9-31.

What measurement do you need to find in order to calculate the area inside the circle?

Recall the equation for area from the Math Notes box in this lesson.

What measurement is missing in this equation?

Find the area inside the circle using the formula

. Write your answer as a product of and, and as an approximation using.Diameter = 2 (radius)

Solve for

.Substitute the newly calculated radius into the area formula.

cm ^{2}