Volume of cylinder radius 5 height 4

Step by step

The question

Question: find the volume of a cylinder with radius 5 and height 4.

1 Circle times height

The top is a circle.

Its area is π × r².

The cylinder is that circle, stacked up 4 high.

π is a special number for circles.

It is about 3.14.

So the volume is V = π × r² × h.

Now put the numbers in: r = 5 and h = 4.

5² means 5 times 5.

That is 25.

So V = π × 25 × 4.

25 times 4 is 100.

So V = 100π.

We keep π in the answer.

That is the exact answer.

2 About how much

To see about how much, put 3.14 for π.

100 times 3.14 is 314.

So the volume is about 314 cubic units.

Let's look back.

First: circle times height.

Last: about how much.