Volume of hemisphere radius 6 cm

Step by step

The question

Question: find the volume of a hemisphere (half a ball) with radius 6 cm.

1 Half of a ball

A hemisphere is half of a ball.

A whole ball is 4/3 × π × r³.

π is a special number for circles.

It is about 3.14.

So the hemisphere is half of it: V = ½ × 4/3 × π × r³.

Half of 4 thirds is 2 thirds.

So V = 2/3 × π × r³.

Now put the numbers in: r = 6.

6³ means 6 times 6 times 6.

That is 216.

So V = 2/3 × π × 216.

Keep the numbers small: divide 216 by 3 first.

216 divided by 3 is 72.

So V = 2 × π × 72.

2 times 72 is 144.

So V = 144π.

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.

144 times 3.14 is 452.16.

So the volume is about 452.16 cm³.

Let's look back.

First: half of a ball.

Last: about how much.