How_To_Be_Good_At_Math

MEASUREMENT • WORKING OUT AREA WITH A FORMULA MEASUREMENT • WORKING OUT AREA WITH A FORMULA

Working out area

with a formula

Using a formula is a much easier way to find a shape’s area

than having to count squares. Calculating with a formula means

you can find the area of large shapes more quickly.

The area of a square

or rectangle is:

length × width

TRY IT OUT

See for yourself

The sandpit in the playground is 4 m long and 2 m wide.

Can you use the formula to find the area of the sandpit?

If we put a square grid over the playground,

we would see eight rows of six 1 m² units,

making a total area of 48 m².

There is a quicker way to find the

area than counting squares. We can

use a formula.

If we multiply 6 by 8, we get 48. This is the

same number as the number of metre

squares we can fit into the playground.

We can write this as a formula that will work

for any rectangle, including squares:

Area = length × width

Look at this playground. We know that it has

a width of 6 m and a length of 8 m.

4 m

2 m

WIDTH

6 m

LENGTH

8 m

Answer on page 319

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