Perimeter
Maths: Year 3 & 4 National Curriculum, topic 2.1.4
Perimeter
The perimeter of a shape is the length of the 'outside' of the shape. You need to add all of the lengths of the shape.
Example 1
- To find the perimeter of this shape, we need to add all the side lengths together.
Example 1 cont.
Example 2
- To find the perimeter of this shape, we need to add all the side lengths.
Example 2 cont.
Missing length
- Sometimes you might need to work out the missing length of a shape in order to find the perimeter.
- What is the perimeter of the rectangle above?
Missing length
- We use the information that rectangles have two pairs of sides of equal length to work out that the length of the missing side is 4 cm.
Test yourself on Perimeter
What is the perimeter of the rectangle below?
What is the perimeter of this equilateral triangle?
What is the perimeter of this rectangle?