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Straight Lines: What's the Unknown Angle?

In this worksheet, students calculate the unknown angle on a straight line.

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'Straight Lines: What's the Unknown Angle?' worksheet

Key stage:  KS 2

Curriculum topic:   Maths and Numerical Reasoning

Curriculum subtopic:   2D Shapes: Circles, Angles and Bearings

Difficulty level:  

Worksheet Overview

This worksheet is about calculating the unknown angle on a straight line.

The angles at a point on a straight line add up to 180°.

180° is half a complete revolution.


 Notice that 35° + 145° = 180°



Find the missing angle in degrees.



The missing angle is 180° - 65° = 115°


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