Question

the radius r of a sphere is 9.4 cm. calculate the spheres surface area a. use the value 3.14 for π, and round your answer to the nearest tenth.

Explanation:

Step1: Write the formula for the surface area of a sphere

The formula for the surface area of a sphere is \(A = 4\pi R^{2}\).

Step2: Substitute the given values

Given \(R = 9.4\) cm and \(\pi=3.14\).
First, calculate \(R^{2}\): \(R^{2}=(9.4)^{2}=9.4\times9.4 = 88.36\).
Then, substitute into the formula: \(A = 4\times3.14\times88.36\).
Calculate \(4\times3.14 = 12.56\).
Now, \(A=12.56\times88.36\).
\(12.56\times88.36=(12 + 0.56)\times88.36=12\times88.36+0.56\times88.36\).
\(12\times88.36 = 1060.32\), \(0.56\times88.36=(0.5 + 0.06)\times88.36=0.5\times88.36+0.06\times88.36=44.18+5.3016 = 49.4816\).
\(1060.32+49.4816=1109.8016\).

Answer:

\(1109.8\)