Calculate Missing Angles in a Quadrilateral

In this activity, we will learn how to calculate missing angles in quadrilaterals.

Remember that quadrilaterals are simply shapes with four sides.

We know that all angles in a quadrilateral add together to make a total of 360°

Let's try an example question together.

Example

Calculate the missing angle in this quadrilateral.

Answer

We know that 126 + 56 + 106 + a = 360

So, to work out a, we need to subtract the other angles from 360.

126 + 56 + 106 = 288

360 - 288 = 72

a = 72°

Let's have a go at some questions now.