Question

the function f(r) gives the area of a circle with radius r. it can be written in equation form as f(r) = 3.14r². what is f(3)? a. 28.26 b. 18.84 c. 12.14 d. 88.74

Explanation:

Step1: Substitute \( r = 3 \) into the function

We have the function \( f(r)=3.14r^{2} \). To find \( f(3) \), we substitute \( r = 3 \) into the function. So we get \( f(3)=3.14\times(3)^{2} \).

Step2: Calculate \( 3^{2} \)

First, calculate the exponent: \( 3^{2}=9 \). Now the function becomes \( f(3)=3.14\times9 \).

Step3: Multiply 3.14 and 9

Multiply \( 3.14 \) by \( 9 \): \( 3.14\times9 = 28.26 \).

Answer:

A. 28.26