7. Measurement

Lesson

Can you find the perimeter of a rectangle where not all the lengths are marked?

Find the perimeter of the rectangle shown.

Worked Solution

Idea summary

The perimeter of a rectangle is given by the formula \text{Perimeter}=2 \times \text{(Length +Width)}

In this video, we deconstruct and reconstruct a rectangle. If we know the perimeter and one of the side lengths we can work out the other.

Find the missing side length of the rectangle shown.

Worked Solution

A part of the perimeter can be considered a fraction of the perimeter.

Consider the square below:

a

If you start at point A and travel clockwise \dfrac12 of the way around the square, where do you end up?

Worked Solution

b

If you start at point A and travel clockwise \dfrac14 of the way around the square, where do you end up?

Worked Solution

Idea summary

We can only use fractions to calculate perimeter this way if our shapes have sides of equal length.