Question

A cylinder’s radius is reduced to 2/5 its original size and the height is quadrupled. How has the volume of the cylinder changed?

A.
The volume is now 8/25 the original volume.

B.
The volume is now 16/25 the original volume.

C.
The volume is now 64/25 the original volume.

D.
The volume is now 16/5 the original volume.

Answer 1

well if you let radius = 1 and height = h

the volume of the cylinder is

\[V = \pi \times1^1\times h = \pi h\]

so if the radius becomes 2/5 and height becomes 4h

then

\[V = \pi \times (\frac{2}{5})^2 \times 4h\]

or

\[V=\frac{16}{25} \pi h\]

what happened to the volume...