PLEASE HELP WITH MATH, REALLY EASY! I just dont get it.?

a sphere has a radius of 13 units

Volume of sphere is 4/3 π r³

V = 4/3 π 13³

= 9,202 cubic units

NOT one of their answers.

Let's try to figure out where they went wrong...

If 13 were diameter, V = 2300un³

even that is not an answer!!!

Let's try surface area: 4πr²

SA = 2,123 un² Nope not that either!!

They really screwed up on the answers. Not the first time I've seen this!

For each, let's find Radius:

A. 2,929.33 cubic units; 8.9

B. 732.33 cubic units; 5.6

C. 225.33 cubic units; 3.8

D. 676 cubic units; 5.4

I really have NO idea where they went wrong!

V=(4pr^3)/3 That should be a familiar formula....

V~2929.33p u^3 you left out the pi from the list of answers...

V~9202.77 u^3 (with pi taken into account)

V≈9202.77

All of the answers are wrong.