Question

1. calculate the exact area of each circle.

a area: _
b area: _

Explanation:

Step1: Recall the formula for the area of a circle

The formula for the area of a circle is \(A = \pi r^{2}\), where \(r\) is the radius of the circle.

Step2: Calculate the area for part a

For part a, assume the radius \(r = 5\) (from the grid - based circle). Substitute \(r = 5\) into the formula:
\(A=\pi\times5^{2}=\pi\times25 = 25\pi\)

Step3: Calculate the area for part b

For part b, the radius \(r = 7.5\) cm. Substitute \(r = 7.5\) into the formula:
\(A=\pi\times(7.5)^{2}=\pi\times56.25=56.25\pi\)

Answer:

a. \(25\pi\)
b. \(56.25\pi\)