Home/Fifth Grade Math/Week 31: Polygons/Lesson 2
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Regular and Irregular Polygons

A regular polygon has all sides and all angles equal. Irregular polygons do not.

Lesson 2

Concept

Polygon = closed figure with straight sides. Regular polygon: - equal side lengths - equal angle measures Examples: regular triangle, square, regular pentagon. Irregular polygon: - at least one side or angle differs. Use side length and angle clues to classify shapes correctly.

Try it

Classify each as regular or irregular: 1. Triangle with sides 5,5,5 2. Rectangle 4 by 7 3. Pentagon with all equal sides and angles 4. Quadrilateral with sides 3,3,5,5 5. Draw one regular and one irregular polygon.