Question

find the area of this circle.
use 3.14 for π.
area of a circle
a = πr²
a = ? cm²
round your answer to the nearest tenth.

Explanation:

Step1: Substitute the radius into the formula

Given the formula for the area of a circle \( A=\pi r^{2}\), and \(r = 7\) cm, \(\pi=3.14\). Substitute \(r\) into the formula: \(A = 3.14\times7^{2}\).

Step2: Calculate \(7^{2}\)

\(7^{2}=7\times7 = 49\). So the formula becomes \(A=3.14\times49\).

Step3: Multiply

\(3.14\times49=(3 + 0.14)\times49=3\times49+0.14\times49=147+6.86 = 153.86\).

Step4: Round to the nearest tenth

The digit in the hundredth place is \(6\). Using the rounding rule (if the digit in the hundredth place \(\geq5\), round up the digit in the tenth place), \(153.86\approx153.9\).

Answer:

\(153.9\)