Calculate the Missing Measures in Composite Rectangles

In this activity, we're going to be using information provided to work out missing measurements.

Things we need to know:

The perimeter of a shape is the total distance around the outside.

A composite/compound rectangle is any shape that is made up of two or more rectangles (including squares).

We can usually use the information provided to work out that which is not provided.

Opposite lengths of a rectangle are equal.

Here is a composite rectangle where one of the measurements is missing.

We know that opposite sides of a rectangle are equal, so we can see that the 4 cm + ? must equal 10 cm.

10 cm - 4 cm = 6 cm

The missing measure is 6 cm.

Top Tips:

Check the unit of measure and remember to include it in your answer.

If asked to work out the perimeter, check the number of sides each shape has and make sure you have included them all.

Some shapes might have two measures missing!

Now it's your turn to have a go.

Good luck!