Content description
Choose appropriate units of measurement for length, area, volume, capacity and mass (ACMMG108)
Calculate the perimeter and area of rectangles using familiar metric units (ACMMG109)
Source: Australian Curriculum, Assessment and Reporting Authority (ACARA)
What is perimeter?
The word 'perimeter' comes from two Greek words; peri, meaning 'around', and metron, meaning 'measure'. So perimeter means the measure or distance around something. It is the length around the edge.
The perimeter of a straightsided twodimensional shape is the sum of the lengths of its sides.
So we can calculate the perimeter of this shape:  Detailed description 

Perimeter  = 8 m + 8 m + 1 m + 2 m + 7 m + 6 m = 32 m 

We can calculate the perimeter of this square:  
P  = 8 m + 8 m + 8 m + 8 m = 32 m 

We can calculate the perimeter of this rectangle:  
P  = 2 m + 14 m + 2 m + 14 m = 32 m 

We can calculate the perimeter of this octagon:  
P  = 4 m + 4 m + 4 m + 4 m + 4 m + 4 m + 4 m + 4 m = 32 m 

We can calculate the perimeter of this triangle:  
P  = 7 m + 12 m + 13 m = 32 m 

You might have noticed that the different shapes have the same perimeter.