Mathematics

Advanced

50 mins

Teacher/Student led

Learning Goals

Learning Outcomes

Lesson Files

+65 XP

What you need:
IWB/Projector/Large Screen
Protractor

Measuring Angles with a Protractor

Learn to position a protractor correctly on an angle's vertex and read the correct scale to measure angles to the nearest degree.

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1 Getting Started
2 Watch and Notice
3 Try It Together
4 Note the Reading in Your Copy
5 Class Challenge
Pupil practice

1 - Getting Started ~4 mins

Here is an angle with a protractor beside it. Where does the protractor need to sit before you can read the angle?

👇 Mark your steps as done as you complete them.

+5 XP

2 - Watch and Notice ~9 mins

Look at these angles measured on the protractor. Each time, check two things: the centre sits on the vertex, and one arm lies along a 0. Look closely at the 145° angle, both scales are showing at once, so you have to pick the ring that starts at 0 on your arm.

This last one is nearly a straight line, so the reading is easy to miss.

👇 Mark your steps as done as you complete them.

+10 XP

3 - Try It Together ~8 mins

Key point

Today we work through three angles together on the board: first 25°, then 115°, then 160°. Before each one, say which scale (inner or outer) you would read and why, then a pupil comes up and drags the arm so we can check.

Read the angle: which scale?

+15 XP

4 - Note the Reading in Your Copy ~2 mins

COPYBOOK MOMENT

In your maths copy, sketch each angle you measure and write its reading underneath, including which scale you used (inner or outer). Underline the trickiest reading of the round.

+10 XP

5 - Class Challenge ~10 mins

What to do

Measure five printed angles with your own protractor. For each one, write the reading and which scale (inner or outer) you read. They get trickier as you go: an acute angle, a right angle, two obtuse angles, and finally one just under a straight line.

Hands-on Task

+15 XP

Pupil practice

Module 6 · 2D and 3D Shape, Angles, Symmetry Shape & Space

Lesson 81 · Measuring Angles with a Protractor

Download Activity Book page (PDF)

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