Year 10 Interactive Maths - Second Edition

Perimeter

Recall that:

Perimeter is the distance around a closed figure.

Perimeters can be measured in millimetres (mm), centimetres (cm), metres (m) and kilometres (km). These units are related as follows:

Perimeters are often required to solve real world problems.

Note:

We use P to denote the perimeter.

Perimeter of a Square

Recall that:

Example 5

Find the perimeter of a square paddock of side 35 m.

Solution:

So, the perimeter is 140 m.

Perimeter of a Rectangle

Recall that:

Example 6

Find the perimeter of a rectangular field of length 50 m and width 40 m.

Solution:

So, the perimeter is 180 m.

Perimeter of a Triangle

Recall that:

Example 7

Find the perimeter, P, of the triangle shown.

Solution:

So, the perimeter is 24 cm.

Perimeter of a Circle

Recall that:

The perimeter of a circle is called the circumference and is represented by C.

Example 8

A circular swimming pool has a radius of 14 m.  Find the circumference of the pool.

Solution:

So, the circumference of the pool is 88 m.

Note:

Example 9

Solution:

Key Terms

perimeter, circumference