# Calculate Angles on a Straight Line

In this worksheet, students will calculate angles on a straight line.

Key stage:  KS 3

Curriculum topic:   Geometry and Measures

Curriculum subtopic:   Apply the Properties of Angles

Difficulty level:

#### Worksheet Overview

In this activity, we are going to look at angles on a straight line.

You will be using written methods for adding and subtracting.

As you know, when we complete 1 full turn we move through 360

A straight line is a half turn, so is therefore, half of 360o

You can see this if you look at a protractor.

Key Point (*Make a note of this)

Angles on a straight line add up to 180°

How would we use this information?

As with the angles at a point, it means that if we are given the sizes of some angles, we can use this fact to find missing angles.

Let's look at an example

Find the missing angle B

The angles on a straight line add up to 180°

B = 180 - 150

B = 3

This is what it would look like on the protractor.

Let's try some of these!

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