Regular and irregular polygons
Distinguish between regular and irregular polygons based on reasoning about equal sides and equal angles
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Teaching Table
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“If you show your child a stop sign (regular octagon) and a wonky eight-sided shape, can they explain which is regular and which is irregular — and why?”
Full guide and materials
- Activity. Distinguish between regular and irregular polygons based on reasoning about equal sides and equal angles
What to notice. Classify a set of polygons as regular or irregular • Explain that a regular pentagon has 5 equal sides and 5 equal angles • Identify that a rectangle is irregular (equal angles but not all equal sides) unless it is a square
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If you show your child a stop sign (regular octagon) and a wonky eight-sided shape, can they explain which is regular and which is irregular — and why?
Distinguish between regular and irregular polygons based on reasoning about equal sides and equal angles
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Check understanding
- Classify a set of polygons as regular or irregular
- Explain that a regular pentagon has 5 equal sides and 5 equal angles
- Identify that a rectangle is irregular (equal angles but not all equal sides) unless it is a square
“If you show your child a stop sign (regular octagon) and a wonky eight-sided shape, can they explain which is regular and which is irregular — and why?”
Curriculum record
- Type
- Conceptual
- Subject
- Mathematics
- Domain
- Geometry
- Age range
- Ages 9–10