Polygon

Closed figure with straight sides

Quadrilateral

4- sided polygon

Trapezoid

A quadrilateral with only one set of parallel lines

Parallelogram

A quadrilateral with two sets of parallel lines

Rhombus

A parallelogram (two sets of parallel sides) with all sides the same length

Rectangle

A parallelogram (two sets of parallel sides) with four right angles, opposite sides are of equal length

Square

A rhombus (2 sets of parallel lines, all sides of equal length) with four right angles

Acute Triangle

A triangle that has all angles less than 90° (90° is a Right Angle)

Right Triangle

A triangle that has a right angle (90°)

Obtuse Triangle

A triangle that has an angle greater than 90°

Equilateral Triangle

A triangle with all three sides of equal length.

All angles are acute.

Isosceles Triangle

A triangle with two equal sides.

The angles opposite the equal sides are also equal.

Scalene Triangle

A triangle with all sides of different lengths.

All angles are
different, too.

Pentagon

5-sided polygon

Heptagon

7-sided polygon

Hexagon

6-sided polygon

Octagon

8-sided polygon

Decagon

10- sided polygon