Area of rectangle 12 by 8 with a 4 by 3 rectangle cut out

Step by step

The question

Question: find the area of this shape: a 12 by 8 rectangle with a 4 by 3 hole cut out.

1 The whole and the hole

The whole shape would be a 12 by 8 rectangle.

A hole is cut out.

That part is not there any more.

So we take it away.

2 Area of each part

The whole rectangle: length times width.

12 times 8 is 96.

The hole is a 4 by 3 rectangle.

4 times 3 is 12.

3 Take away the hole

The area is the whole, take away the hole.

96 minus 12 is 84.

So the area is 84 square units.

4 Check

Let's check: put the hole back.

We should get the whole rectangle.

We get 96, the whole rectangle.

So the area is right!

Let's look back.

First: the whole and the hole.

Then: area of each part.

Then: take away the hole.

Last: check.