In this activity, we'll be working out the perimeter of 2D shapes.
The perimeter of a shape is simply the distance around the outside of the shape.
When working out the perimeter we must make sure that we check the unit of measure - is it measured in mm, cm, m, km, or something else?
Sometimes we need to use a ruler to work out the perimeter.
In this activity, we will be given most of the measurements, so we won't need a ruler.
We'll need to work out some measurements using the information we have been given.
Let's get started.
Here is a rectangle:
The short side (height) is 6 cm long.
The long side (width) is 10 cm long.
We have been given two of the measurements - 6 cm and 10 cm.
It is a rectangle, so we know that the opposite sides will be equal.
So we can see that we have two sides of 10 cm = 20 cm.
We also have two sides of 6 cm = 12 cm.
Now we add these together to get the measurements of all four sides:
20 cm + 12 cm = 32 cm
The perimeter of the rectangles is 32 cm. This is the length of all four sides added together.
Now it's your turn to have a go!