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Singapore Primary Maths

Primary 4 maths · Geometry · About 10 minutes

Use rectangle and square properties excluding diagonals

Follow the full boundary and check the features needed for its name.

Start the interactive lesson →Open practice activity

What you will learn

Models used: number sentences, stories, diagrams.

Before you start

A turn does not change the shape

Look for straight sides, corners and curved boundaries.

  1. Look for straight sides, corners and curved boundaries.

    Follow the sides and corners.
  2. Turn the shape. Its sides are still the same length, and its corners have the same openings.

    Turning a figure changes where it points. It keeps its side lengths and corner angles, so it is still the same shape.

    Follow the sides and corners.
    The same figure, turned through 25 degrees.
  3. Use those features to recognise the shape, whichever way it is turned.

    Turning a figure changes where it points. It keeps its side lengths and corner angles, so it is still the same shape.

    Follow the sides and corners.
    Changing orientation preserves the shape.
What did the picture help us see?

Use those features to recognise the shape, whichever way it is turned.

Worked example: A new example, together

Which property must every square have?

Use side and angle properties; diagonal properties are not required.
  1. Follow the full boundary and check the features needed for its name.

    Four equal sides and four right angles

    Use side and angle properties; diagonal properties are not required.
  2. Check the number of sides.

    Use side and angle properties; diagonal properties are not required.
    Which property must every square have?

    Four equal sides and four right angles

  3. Check the angles at the corners.

    Use side and angle properties; diagonal properties are not required.
  4. Four equal sides and four right angles.

    Use side and angle properties; diagonal properties are not required.
  5. Check the result against the question we started with.

    Measure every corner with a set square and compare the appropriate side lengths.

    We found Four equal sides and four right angles. Four equal sides and four right angles

    Use side and angle properties; diagonal properties are not required.

Common mistakes to discuss

Check your understanding

Explain your reasoning to an adult, then try a fresh question in the interactive lesson. A result from one attempt is not proof of lasting mastery.

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