Question

find the area of a circle with diameter 18 in. use the value 3.14 for π, and do not round your answer. be sure to include the correct unit in your answer.

Explanation:

Step1: Find the radius

The radius \(r\) of a circle is half of the diameter \(d\). Given \(d = 18\) in, so \(r=\frac{d}{2}=\frac{18}{2}=9\) in.

Step2: Use the area formula

The formula for the area \(A\) of a circle is \(A=\pi r^{2}\). Substitute \(\pi = 3.14\) and \(r = 9\) into the formula. Then \(A=3.14\times9^{2}\).
First, calculate \(9^{2}=81\). Then \(A = 3.14\times81\).
Multiply \(3.14\times81=(3 + 0.14)\times81=3\times81+0.14\times81=243+11.34 = 254.34\).

Answer:

\(254.34\ \text{in}^{2}\)