Angles in Shapes

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1 Getting Started
2 Watch and Notice
3 Try It Together
4 Mark the Corners in Your Copy
5 Class Challenge
6 What Did We Notice?
7 What's Next
Pupil practice

1 - Getting Started ~4 mins

Illustration for Getting Started Look at these three shapes on the board: a square, a triangle and a hexagon. Every corner is a little turn from one side to the next, so every corner is an angle. Hands up: which shape do you think has square-corner angles like the corner of a window?

Teacher Notes

Take three hands-up answers, not open call-outs. Give five seconds of quiet think-time first. Do not confirm which shape has right angles yet — that lands in the next step.

👇 Mark your steps as done as you complete them.

+5 XP

2 - Watch and Notice ~9 mins

Look at each shape and its corners. Every corner is an angle. We will also bring in a rectangle here, a new shape, so we can compare its corners with the square's. For each shape, look at its corners and be ready to say how many there are, and whether each one looks like a square corner, a sharper corner, or a wider corner.

Teacher Notes

Square — reveal the four corners; hold out for pupils to notice each one looks like a square corner.
Rectangle — four corners again, all square corners; this is a new shape here, so ask what is the same as the square.
Triangle — three corners; ask which corner looks sharpest.
Hexagon — six corners, all a bit wider than a square corner; do not name them yet, just have the class notice they open wider.

Say every corner is an angle at least twice across the four shapes.

👇 Mark your steps as done as you complete them.

+10 XP

3 - Try It Together ~8 mins

Key point

This time the class decides before we look. For each shape, first predict every corner: thumbs up for a square corner, thumbs sideways for sharper, thumbs down for wider. Then we reveal the corners and check who was right. We do this for the square, then the rectangle, then the triangle, then the hexagon.

Predict, then reveal the corners

Teacher Notes

We are talking this one through together as a class. Nobody is being marked yet.

In Watch and Notice you revealed and the class watched; here the class predicts each corner before the reveal, so every pupil commits an answer on every shape. For each shape, ask the whole class to predict with the thumbs signal (up = square corner, sideways = sharper, down = wider) before anything is revealed. Then a pupil comes up to reveal and count the corners, and the class checks its prediction against what appears. Rotate a different pupil for each shape so the reveal keeps moving, while the whole class stays active through the thumbs prediction. Revoice a strong answer: so a square's corners are all square corners, but a hexagon's corners are wider. Keep the board work brisk.

+15 XP

4 - Mark the Corners in Your Copy ~3 mins

COPYBOOK MOMENT

First watch the board. We draw one square, then at each right-angle corner we draw a tiny square inside the corner. That little square is the right-angle symbol. Check all four corners get the same mark.

In your maths copy, draw a square and mark each right-angle corner with the little square symbol. Then draw a triangle and mark its smallest corner.

Teacher Notes

Board demo first, before anyone opens a copy. Draw one clear square. At one corner, draw a small open square snug into the angle and say: this little square means right angle. Mark the other three corners the same way so pupils see four identical marks. Then send them to copies: square with four little-square marks, then a triangle with one clear mark on its sharpest corner.

Walk the room, glance for the little square symbol in all four corners of the square and one clear mark on the triangle's sharpest corner. No individual marking, this is whole-class copybook practice, not assessment. Slip to watch: pupils drawing a filled blob or a curve instead of a small open square, or marking only one corner of the square.

+10 XP

5 - Class Challenge ~11 mins

Key point

Now we test real shape cards with the paper right-angle tester. First make your tester: fold your sheet of paper in half, then fold it in half again. The new corner where the folds meet is a sharp square corner.

Then check the corners of these shapes in turn: a square, a triangle, a wide triangle, and a rectangle. Slot the paper corner into each one and see if it fits exactly, or is too small, or too big.

Hands-on Task

Teacher Notes

This is the challenge round. Pupils work it themselves and check their own answers.

Real shape cards circulate around the room and pupils test each corner with their own paper tester. Keep the pass-on rhythm brisk; the class confirms each reading aloud at the end. The wide triangle card must be an obtuse triangle with one corner clearly larger than 90° — check your card set has one before the lesson, otherwise the 'bigger than a right angle' test will fail. Run the corners in rising difficulty: (1) a square corner — the tester fits exactly, a right angle; (2) the sharpest corner of a triangle — smaller than a right angle; (3) the wide corner of the obtuse triangle — bigger than a right angle; (4) count how many right angles a rectangle has. On the almost-square corner, hold out for the tester test before the class decides. Watch that pupils line the fold up into the very point of the corner.

+15 XP

Pupil practice

Module 7 · 2D and 3D Shapes and Angles Data & Chance

Lesson 82 · Angles in Shapes

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This lesson is copyright of Coding Ireland 2017 - 2025. Unauthorised use, copying or distribution is not allowed.

Teacher Class Feed

1 - Getting Started ~4 mins

2 - Watch and Notice ~9 mins

3 - Try It Together ~8 mins

Predict, then reveal the corners

4 - Mark the Corners in Your Copy ~3 mins

5 - Class Challenge ~11 mins

Hands-on Task

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