Grade 4 - Progress in Mathematics

Polygons

10-5

Prefix Number of Angles Polygon Name

tri- 3 triangle

quadri- 4 quadrilateral

penta- 5 pentagon

hexa- 6 hexagon

octa- 8 octagon

These figures are all polygons:

The sides of a polygon are line

segments that do not cross.

Tw o sides of a polygon form an angle

when they meet at a common endpoint

called a vertex (plural: vertices).

4 sides 8 sides

4 vertices 8 vertices

Most polygons are named for the number

of angles they have.

sides

vertices

sides

Remember: Polygons are closed

plane figures with straight sides.

These are regular polygons,

because they each have

sides of equal length and

angles of equal measures.

Polygonmeans

“many angles.”

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