A sphere is a round ball, like a basketball or a baseball or a planet:
It is a solid 3-dimensional figure where all points on it's surface are the same distance
from the center of the figure.
If you have a sphere whose radius is R, then
its volume (V) is:             V = 4R3/3
and its surface area (A) is A = 4R2
Here is a problem for you (use your calculator):
- The radius of a basketball is 4.5 in.   call this r1
- The radius of a baseball is 1.25 in.   call this r2
- What is the volume of a basketball? v1 = ____________ cu. in.
- What is the volume of a baseball?   v2 = _____________ cu. in.
- What is the ratio of the volume of a basketball to the volume of a baseball?
Ratio = v1⁄v2 = ____________ / ______________ = ______________
This is how many baseballs fit inside a basketball!