Angles: What Is an Angle?

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1 Getting Started
2 Watch and Notice
3 Try It Together
4 Sketch the Angles in Your Copy
5 Quarter-turn Compass Game
Pupil practice

1 - Getting Started ~3 mins

Watch carefully. I am going to stand here, then turn to face the door. How much did I turn? Was it a small turn, a quarter turn, a half turn, or all the way round?

Look at the clock on the board too. The two hands at 3:00 make a sharp square corner, just like the corner I turned through. That amount of turn is called an angle.

Key point

Today we name four different angles by how much they turn.

Teacher Notes

Stand at the front, then make a clean quarter-turn to face whichever wall sits at a right angle to your start. Give five seconds of quiet think-time before any hands go up. Point briefly at the clock image to anchor the connection: the body turn and the clock hands are showing the same quarter turn.

👇 Mark your steps as done as you complete them.

+5 XP

2 - Watch and Notice ~8 mins

Watch as the orange ray on the angle-tool makes four different angles. Notice that each one is named by how MUCH the ray has turned, not by how long the rays look.

Right angle (90°)

A quarter turn. The two rays meet at a sharp square corner, just like the corner of your maths book.

Acute angle (less than 90°)

Smaller than a right angle. A narrow, sharp opening, like the hands of a clock just after one o'clock.

Obtuse angle (more than 90°, less than 180°)

Bigger than a right angle but not yet straight, like a laptop opened wider than a square corner.

Straight angle (180°)

A half turn. The two rays now point in opposite directions and make one straight line.

Teacher Notes

Walk each example aloud, one at a time. Point to the vertex (where the two rays meet) on the IWB so pupils know exactly where to look.

Right (90°), say 'a quarter turn, exactly the corner of a square'. Ask the class to point to a right angle they can see in the room.
Acute (45°), say 'smaller than a quarter turn, a sharp narrow opening'.
Obtuse (130°), say 'past a right angle but not yet straight'. This is the trickiest one to name on sight; spend an extra moment here.
Straight (180°), say 'a half turn, the two rays make one straight line'.

👇 Mark your steps as done as you complete them.

+10 XP

3 - Try It Together ~11 mins

Today we name each angle the orange ray makes. As I drag the ray slowly, everyone calls out together: acute, right, obtuse, or straight.

Tip

Then one pupil takes a turn at the board. While that pupil is dragging, the rest of us watch where the ray lands and name the angle aloud together.

Drag the orange ray and name the angle

Teacher Notes

This round is for talking it through together. Pupils take turns at the board and the class agrees or corrects out loud.

Drag the ray slowly through the full range. Pause at clear examples (around 30°, 60°, 90°, 120°, 160°, 180°) and let the class name the angle. When you call up an individual pupil, give them a named target ('set it to an obtuse angle, somewhere bigger than 100°') rather than an exact number, keep this round about naming the type, not yet about precision.

Watch for the obtuse-vs-straight slip: pupils sometimes call 160° straight because it looks close. Drag a clear 180° straight after each obtuse to reset the contrast.

+15 XP

4 - Sketch the Angles in Your Copy ~3 mins

COPYBOOK MOMENT

In your maths copy, sketch one example each of the four angle types: right, acute, obtuse, and straight. Label each one with its degree range. Mark the right angle with a small square at the vertex so anyone reading your page knows it is exactly 90 degrees.

Teacher Notes

Walk the row glancing at the small square marker on the right angle and the relative sizes of acute against obtuse, this is whole-class copybook practice, not marking.

+10 XP

5 - Quarter-turn Compass Game ~9 mins

Going outside

Take the class to whichever open space your school has room in — the yard, the hall, the corridor, or even beside the desks if no other space is free. Pupils stand facing the same starting direction (call it 'north'); they reset to face north between calls so every turn starts fresh.

Materials

chalk

Plan

Everyone face north. This is our starting direction, and every turn starts here.
Make a small turn to your right, less than a quarter turn. That was an acute angle, smaller than 90 degrees. Now turn back to face north.
Quarter turn right. You now face east. That was a right angle, exactly 90 degrees. Now turn back to face north.
Turn right by more than a quarter but less than a half. That was an obtuse angle, between 90 and 180 degrees. Now turn back to face north.
Half turn all the way around. You now face south. That was a straight angle, 180 degrees.
On the walk back to the classroom, find one example each of a right angle, an acute angle, an obtuse angle, and a straight angle.

If you can’t go out: indoor alternative

Run the compass game indoors. Pupils stand beside their desks and turn in place, resetting to face the front of the room between calls. For the angle-spotting, look around the classroom: book corners, door frames, the lid of an open laptop, the hands of the wall clock.

Teacher Notes

Run the calls brisk: about thirty seconds each, including the reset back to north. Always reset to face north between calls, so each named angle is the angle of that one turn, not a running total.

Name the angle aloud immediately after each turn ('that was a right angle, 90 degrees'). Watch for pupils who turn the wrong way; have them check against their neighbour to recalibrate before the next call.

For the angle-spotting after the turns, point out one or two yourself to start the eyes off (a window corner is a right angle; a door propped open is obtuse) and let the class find the rest.

+15 XP

Pupil practice

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

Lesson 75 · Angles: What Is an Angle?

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Teacher Class Feed

1 - Getting Started ~3 mins

2 - Watch and Notice ~8 mins

Right angle (90°)

Acute angle (less than 90°)

Obtuse angle (more than 90°, less than 180°)

Straight angle (180°)

3 - Try It Together ~11 mins

Drag the orange ray and name the angle

4 - Sketch the Angles in Your Copy ~3 mins

5 - Quarter-turn Compass Game ~9 mins

Materials

Plan

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