Question

What is the surface area of a sphere with a radius of 16 units?

Answer 1

we know that

The surface area of a sphere is equal to

$SA=4\pi r^{2}$

where

r is the radius of the sphere

in this problem we have

$r=16\ units$

substitute in the formula

$SA=4\pi(16^{2})$

$SA=1,024\pi\ units^{2}$

or

$SA=3,216.99\ units^{2}$

therefore

the answer is

$SA=1,024\pi\ units^{2}$

Answer 2

Formula of surface area of a sphere is 4$\pi r^{2}$. 
Hence it is 4$\pi 16^{2} ≈ 3216.99 ≈3217$