Question

A cylinder has a radius of 4.5 inches and a height of 15 inches. If the radius is doubled, how would it affect the original volume of the cylinder?

Answer 1

The volume will be increased 4 times.

Explanation:

Short mathy expl:

If the radius is "doubled" that is 2 times bigger. But in the volume formula, the radius is squared. So 2 times bigger AND squared makes it FOUR times bigger.

See the volume calculations:

original--

Vol = pi•r^2•h

= (3.14)•4.5^2•15

= 953.775

new/bigger radius--

Vol = 3.14•9^2•15

= 3815.1

So when the radius is doubled, going from 4.5 to 9, the volume goes from 953.775 to 3815.1

3815.1 is 4 times 953.775