Volume of cylinder radius 2 cm height 7 cm

Step by step

The question

Question: find the volume of a cylinder with radius 2 cm and height 7 cm.

1 Circle times height

The top is a circle.

Its area is π × r².

The cylinder is that circle, stacked up 7 cm 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 = 2 and h = 7.

2² means 2 times 2.

That is 4.

So V = π × 4 × 7.

4 times 7 is 28.

So V = 28π.

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.

28 times 3.14 is 87.92.

So the volume is about 87.92 cm³.

Let's look back.

First: circle times height.

Last: about how much.