Classifying Quadrilaterals

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1 Getting Started
2 Watch and Notice
3 Try It Together
4 Sketch the Shapes 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 a window, a kite and a slice of cake from above. Each one has four straight sides. But are they all the same kind of four-sided shape? Some have equal sides, some have square corners, and some lean over. Today we will sort four-sided shapes into named families.

Teacher Notes

Take three hands-up answers naming what is the same about all three (four sides). Do not name the families yet — that is the Watch and Notice step's job. Give five seconds of quiet think-time before any hands go up.

👇 Mark your steps as done as you complete them.

+5 XP

2 - Watch and Notice ~9 mins

Here are five four-sided shapes, each with its rule. Look at the sides and the corners of each shape. Notice which shapes lean and what stays the same about their sides and corners.

Teacher Notes

Square: four equal sides, four right angles. Hold a copybook corner against one corner to show the right angle.

Rectangle: opposite sides equal, four right angles.

Rhombus: four equal sides like the square, but it leans, so corners are no longer square.

Quick check before the last two: pause here. Ask one pupil for the difference between square and rhombus (both four equal sides, only the square has square corners; rectangle keeps right angles and opposite sides equal). Spaces the harder distinctions.

Parallelogram: take slowly against the rhombus. Both lean; rhombus has all four sides equal, parallelogram only opposite sides equal and parallel.

Trapezium: the slip is thinking two pairs are parallel. Point clearly to the one pair; the other two sides are not parallel.

👇 Mark your steps as done as you complete them.

+10 XP

3 - Try It Together ~11 mins

Today we work through these together. I show a four-sided shape card, and from your seat you run the checking routine in your head along with the pupil at the board: are the sides equal? how many pairs of parallel sides? are the corners square? Then we agree as a class which family it belongs to — square, rectangle, rhombus, parallelogram or trapezium.

Sort the quadrilateral into its family

Teacher Notes

This round is for talking it through together — a pupil sorts at the board while the seated class follows the same checking routine and agrees or corrects out loud.

Have the pupil check three things in order before they sort: are the sides equal? how many pairs of parallel sides? are there right angles? Revoice a strong answer: so opposite sides equal plus right angles makes it a rectangle. Rotate five pupils so each family gets named.

+15 XP

4 - Sketch the Shapes in Your Copy ~3 mins

COPYBOOK MOMENT

A property is something that is true about a shape — its sides, its corners or its parallel sides. In your maths copy, draw a square, a rectangle and a parallelogram. Beside each one, write one property that makes it special.

Teacher Notes

Walk the room glancing at the property each pupil wrote — no marking, this is whole-class copybook practice. Accept any true property (equal sides, right angles, parallel sides).

+10 XP

5 - Class Challenge ~8 mins

Now we build and change shapes — with straws or on the board. Build a square, then lean it over to make a rhombus. Build a rectangle, then lean it into a parallelogram. Each time, say what stayed the same and what changed. After each build, we use the screen to name the shape we made.

Match each built shape to its name

Teacher Notes

The straw build is the main work; the on-screen drag-sort is a quick whole-class confirmation of the name after each build, kept short. The board sort is a name check, not the practice body.

Hand each group of four a set of straws or strips (or run it on the board if straws are not available). Run it as a open-ended making task: (1) build a square; (2) lean it into a rhombus — sides stay equal, corners stop being square; (3) build a rectangle; (4) lean it into a parallelogram. Stretch: build a trapezium and prove it has exactly one pair of parallel sides. Watch for the rhombus/square slip — equal sides do not guarantee right angles.

+15 XP

6 - What Did We Notice? ~3 mins

MATHS TALK

How is a square also a special rectangle? Think about the corners first, then the sides.

Teacher Notes

Listen for pupils noticing that a square has the rectangle's two rules (opposite sides equal, four right angles) AND an extra one (all four sides equal). Revoice: so every square passes the rectangle test, which makes it a special kind of rectangle. Head off the reverse claim — not every rectangle is a square.

+10 XP

7 - What's Next ~2 mins

Today's key ideas

A quadrilateral is any flat shape with four straight sides.
We name the family by checking equal sides, parallel sides and right angles.
A square is a special rectangle: it has four right angles like a rectangle, plus four equal sides.

Coming up

Next we look at polygons with more sides — pentagons, hexagons and octagons — and decide whether they are regular or irregular.

Teacher Notes

Keep this brief. The pupil-practice activity-book page follows the IWB arc.

+5 XP

Pupil practice

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

Lesson 79 · Classifying Quadrilaterals

Download Activity Book page (PDF)

End of lesson

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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 ~11 mins

Sort the quadrilateral into its family

4 - Sketch the Shapes in Your Copy ~3 mins

5 - Class Challenge ~8 mins

Match each built shape to its name

6 - What Did We Notice? ~3 mins

7 - What's Next ~2 mins

Today's key ideas

Coming up

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