Polygons are many-sided figures, with sides that are line segments. Polygons are named according to the number of sides and angles they have.

Can be “regular” – all sides and all angles are equal to each other

All sides are congruent

All angles are congruent

Not all sides are congruent

Not all angles are congruent

5 sides5 angles5 vertices

Regular polygon

Irregular polygon

6 sides6 angles6 vertices

Regular polygon

Irregular polygon

7 sides7 angles7 vertices

Regular polygon

Irregular polygon

8 sides8 angles8 vertices

Regular polygon

Irregular polygon

9 sides9 angles9 vertices

Irregular polygon

Regular polygon

10 sides10 angles10 vertices

Irregular polygon

Regular polygon

Two sides of equal length

Three acute angles Sum of angles =

180°

All sides equal length

Three acute angles Sum of angles =

180° Is a regular

polygon

No sides are equal No angles are

equal May have obtuse

angle Sum of angles =

180 °

Has one 90 ° angle

Sum of all angles 180 °

A triangle having three acute angles.

Sum of angles = 180°

A triangle having an obtuse angle.

Sum of all angles 180 °