Math · Stage 4

Measure and draw angles; identify symmetry; reason about angles

Measure and draw angles with a protractor, spot a line of symmetry, and reason with two facts: a right angle is 90° and the angles on a straight line add to 180°.

✦ Math📘 Stage 4 · S4⏱ ~10 min🧒 Ages 8–9★ Free to start

I can measure and draw angles with a protractor, identify symmetry, and reason about angles using the facts that a right angle is 90° and angles on a straight line add to 180°.

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Kavi's Protractor & the Folding Wing 📐

Kavi opens a half-moon ruler with numbers around the edge. "This is a protractor — it measures how wide an angle opens, in degrees (°)!" Kavi points to a square corner: "This one is a right angle — exactly 90°." Then Kavi folds a butterfly's wings together so they match perfectly. "When both halves match on a fold, that fold is a line of symmetry 🦋. Let's measure, draw, and reason about angles!"

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What your child will learn

1A right angle is 90°, a straight line is 180°We measure how far an angle opens in degrees (°). Two sizes are worth memorising — they let you reason about every other angle. Tap each card to meet them.

2Clock hands make a 90° right angleAt 3 o'clock the hour hand points to 3 and the minute hand points to 12. The two hands open to make a perfect square corner — a right angle of 90° 🕒.

3Fold it — do the halves match?

4Measure with a protractor, then name the sizeTo measure or draw an angle, put the protractor's centre on the vertex (the point where the two arms meet), line 0° up along one arm, and read the number where the other arm crosses the scale. Tap each card.

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A peek inside

Two angles sit on a straight line. One of them is 110°. How big is the other angle?

angles on a straight line add to 180°, so 180 − 110

Try this at home: A right angle measures ___ degrees.

Ready to play and learn?

Start the free interactive lesson, or print the handout for screen-free play.

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Part of Math · Stage 4 · S4 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.