Question

If the surface area of a sphere is 256π cm2, what is the radius?
4 cm
8 cm
12 cm
16 cm

Answer 1

8.

If you rearrange the equation for surface area to solve for r then you can plug the 256pi into the equation and get 8. 

Answer 2

The formula for surface area of the sphere is -

Surface area of sphere = 4πr²

Now, the surface area of sphere is given to us as = 256π cm²

Thus,

4πr² = 256π cm²

While equating the equations, we will get

4r² = 256 cm²

r² = 64 cm²

64 is the square of 8, thus the radius of sphere will be = 8 cm.

The correct answer will be = 8 cm radius