Measure the size of angles accurately using a protractor

I can measure the size of angles accurately using a protractor.

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Measure the size of angles accurately using a protractor

I can measure the size of angles accurately using a protractor.

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Key learning points

A protractor is an angle measurer.
Protractors have two scales from 0 to 180 degrees.
Start from zero when reading the scale on a protractor.
Line the protractor up with one of the lines forming the angle.

Keywords

Angle - An angle is a measure of turn. It shows how far something has rotated. It is often displayed as the rotation between two line segments.
Point - A point is an exact location. It has no size, only position.
Vertex - A vertex is a point where two or more lines meet.
Scale - A scale is a number line with equal divisions for equal values.

Common misconception

Pupils incorrectly place the protractor on the angle and therefore cannot measure the angle. Pupils use the incorrect scale to read the angle.

Stress the importance of using the middle spot on the protractor to line this up with the vertex of the angle as well as placing one of the lines on a zero line, ensuring the remaining line crosses the scale of the protractor.

Encourage pupils to explain how other pupils have incorrectly attempted to measure an angle using a protractor. Highlighting these misconceptions can benefit everyone in deepening their understanding for how to measure using a protractor.

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Licence

This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).