Polygons and Quadrilaterals

Polygons and Quadrilaterals

What students learn

Students learn that polygons are closed shapes made of straight sides and that quadrilaterals are a family of four-sided polygons. Start with Polygons: Closed Shapes with Straight Sides to notice the pattern in the shape names.

Why it matters

Classifying shapes helps students see relationships instead of memorizing isolated labels. Polygons: Count Sides to Name Them shows how side count helps students sort triangles, pentagons, hexagons, and other polygons.

Learn the idea

A polygon must be closed and made only of straight line segments. Four-sided polygons form a special group called quadrilaterals. Watch Quadrilaterals: Four-Sided Shapes and Shape Families to see how squares, rectangles, rhombuses, and trapezoids fit inside that group.

Try it

Ask the student to draw three polygons and one shape that is not a polygon. Then have them name each polygon by the number of sides and explain why the non-example does not belong.

Parent guide

Use paper cutouts or classroom objects if needed. Ask, 'Is it closed? Are all the sides straight? How many sides does it have?' before naming the shape.