Angle Twins
An angle is formed by two arms meeting at a vertex. To compare angles, focus on the amount one arm would turn to reach the other across the marked opening. The length of either arm does not tell you how large the angle is.
Before you try
Can a small drawing show a larger angle than a large drawing?
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What happened?
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The game practises one idea at a time with simple drawn pictures. Check the same idea with real objects and your NCERT textbook (Chapter 2: Shapes and Angles, pages 17–18).
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Try these ideas
- Turn the cards and find the same twin again.
- Compare one narrow and one wide opening.
- Use a paper tester to copy a card’s angle.
Why it works
An angle is formed by two arms meeting at a vertex. To compare angles, focus on the amount one arm would turn to reach the other across the marked opening. The length of either arm does not tell you how large the angle is.
Two matching angles may face different ways. Imagine placing their vertices together and lining up one arm. If their other arms also line up, the openings are equal. An angle tester does the same job with two movable strips.
When several angles are shown together, compare the marked openings rather than the overall size of the drawings. A long narrow V can have a smaller angle than a short wide V. Rotating an entire angle leaves its size unchanged; moving just one arm changes it.
Worked example: Angle A is 60° with long arms. Angle B is 90° with short arms. Which is bigger? Ignore the lengths of the arms. Compare the openings: 90° is greater than 60°. Angle B is bigger even though its drawing is smaller.
Check your understanding
Question 1 of 2
What changes an angle’s size?
Two right angles face different directions. They are…
Explain it in your own words
What changed? Why did it happen? Where might you notice this in everyday life?
For parents & teachers
- Tester twins · 8 minutes. Make an angle using two card strips. Draw matching copies with long and short arms, then turn the pages.
- Biggest-angle hunt · 5 minutes. Sketch three V-shaped openings. Ask for the widest one and a reason that does not mention the arm lengths.