This video looks at using the properties of rectangles to calculate the perimeter, it also talks about some special notation that is often used to show when two sides have the same length.

Loading video...

Examples

Example 2

Find the perimeter of the rectangle shown.

The image shows a rectangle with width of 9 metres and length of 23 metres.

Worked Solution

Create a strategy

We can use the formula for a rectangle: \text{Perimeter}=2 \times (\text{Length} + \text{Width} ).

Apply the idea

First add the length and width:

\displaystyle \text{Length$+$Width}	\displaystyle =	\displaystyle 23+9	Add the values
	\displaystyle =	\displaystyle 32 \text{ m}

Now multiply this by 2 to get the perimeter:

\displaystyle \text{Perimeter}	\displaystyle =	\displaystyle 2 \times (\text{Length} + \text{Width} )	Use the formula
	\displaystyle =	\displaystyle 2 \times 32	Double 32
	\displaystyle =	\displaystyle 64 \text{ m}

Idea summary

Because a rectangle has 2 pairs of sides with equal length, we can add the length and width, then double it, to find the perimeter of a rectangle.

A square is a special kind of rectangle, with 4 sides the same length, so we can multiply its side length by 4.

7.03 Perimeter of rectangles

Ideas

Are you ready?

Examples

Example 1

Perimeter of rectangles

Examples

Example 2

Outcomes

ACMMG109

What is Mathspace

About Mathspace