lesson
Compare angles with a right angle
1 · Learn
An acute angle is smaller than a right angle. An obtuse angle is larger than a right angle but smaller than a straight angle. A straight angle equals two right angles.
The length of the drawn arms does not determine the angle. Compare how far one direction turns to the other, not how long the lines are.
2 · Worked example
I overlay a paper right-angle corner on a drawn angle. If the opening is smaller, the angle is acute even if its arms are long.
3 · Your turn
Is an angle just larger than a right angle but smaller than a straight angle acute or obtuse? Does extending its arms change its size?
Check your answer
Obtuse. Extending the arms without changing their directions does not change the angle.
4 · Apply your learning
Draw and order four angles from smallest to largest using a right-angle reference. Keep the same starting direction when comparing.
Adult guidance and safety
Use practical or drawn representations and explain the method. Check units and labels. A correct answer to one example is not evidence of secure fluency; revisit with varied numbers and feedback.
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