Question

calculate the area of the circle. formula: $a = \pi r^{2}$ use 3.14 for pi. $a = ? cm^{2}$ round to the nearest tenth.

Explanation:

Step1: Substitute the radius into the formula

Given the radius \( r = 20\) cm and the formula \( A=\pi r^{2}\), substitute \( r = 20\) and \(\pi=3.14\) into the formula.
\(A = 3.14\times(20)^{2}\)

Step2: Calculate the square of the radius

First, calculate \(20^{2}=20\times20 = 400\).
Then the formula becomes \(A = 3.14\times400\)

Step3: Perform the multiplication

\(3.14\times400=(3 + 0.14)\times400=3\times400+0.14\times400=1200+56 = 1256.0\)

Answer:

\(1256.0\)