Answer:
C
Step-by-step explanation:
The rubber exercise ball is a sphere
the volume of a sphere= 4/3*pi*r3
where r = the radius of the sphere.
from the diagram, the radius = 4.5inches
Therefore, volume of the rubber ball = 4/3*pi*4.5^3 = 381.51 cubic inches
I would do this by first listing the multiples of 6 until I start to see a pattern with the one's digit.
6x0=0
6x1=6
6x2=12
6x3=18
6x4=24
6x5=30
6x6=36
6x7=42
6x8=48
...
The digits in bold are the one's digits so those are the only ones we really care about. If you list just them it looks like: 0,6,2,8,4,0,6,2,8
Notice how the first set of 5 numbers seems as though it repeats in the 6th, 7th, and 8th numbers. This probably means the pattern continues infinitely so the first 5 numbers are all the one's digits that can come from multiples of 6. Thus your answer is: 0,6,2,8,or 4
You can use the trigonometric identity

.

The requirement that

eliminates -1/6 from being another solution.