Year 7. Area

The area of a shape is the amount of space it takes up.

We normally measure area by looking at how many centimetre squares a shape covers (of course, it could include part squares).

We say that a shape that covers 7 centimetre squares has an area of 7cm².

Exercise 1

Small shapes

If you tried to measure a pin head with centimetre squares, you might find it a bit difficult.

Thankfully we can use millimetre squares. Because a millimetre is ten times smaller than a centimetre, so a square millimetre is a hundred times smaller than a square centimetre.

If we know what something measures in centimetres squared, it is easy to convert it to millimetres squared, we just multiply the number by one hundred. What about converting in the other direction? Let’s try some.

Exercise 2

Big shapes

It would take quite a while to measure out the floor space in the school using square centimetres or square millimetres.

But don’t worry!

Because we can use square metres. Because 1m is 100cm, so 1m² is 100 x 100 = 10 000cm². And 1m² is 1000 x 1000 = 1 000 000mm².

Let’s try some conversions again!

Exercise 3

Areas of recangles

When we are finding the area of a rectangle, we can use a shortcut. Instead of counting all of the square centimetres inside it, we can see how many centimetres long its length is and how many centimetres long its width is and multiply them together to find its area. We can see this in the diagram below and then practice the idea in the following exercise.