Content of the Lesson

Facts about SHAPES

A polygon is a plane (2 dimensional) figure that features at least 3 straight sides and angles.
A regular polygon has sides which are all the same length as well as angles which are all the same. Examples of regular polygons include the equilateral triangle and square.
A triangle is a 3 sided polygon with interior angles that add to 180 degrees.
A square is a 4 sided polygon with interior angles that add to 360 degrees. A square is also a type of quadrilateral.
A pentagon is a 5 sided polygon with interior angles that add to 540 degrees.
Regular pentagons have sides of equal length and interior angles of 108 degrees.
The US Department of Defense headquarters is named 'the Pentagon' .
The edible plant okra is shaped like a pentagon.
A hexagon is a 6 sided polygon with interior angles that add to 720 degrees.
Regular hexagons have sides of equal length and interior angles of 120 degrees.
Beehive cells are hexagonal.
A heptagon is a 7 sided polygon with interior angles that add to 900 degrees.
Regular heptagons have sides of equal length and interior angles of 128.57 degrees.
The British 50 and 20 pence coins are curved heptagons.
An octagon is an 8 sided polygon with interior angles that add to 1080 degrees.
Regular octagons have sides of equal length and interior angles of 135 degrees.
A nonagon is a 9 sided polygon with interior angles that add to 1260 degrees.
Regular nonagons have sides of equal length and interior angles of 140 degrees.
A decagon is a 10 sided polygon with interior angles that add to 1440 degrees.
Regular decagons have sides of equal length and interior angles of 144 degrees.
An pentadecagon is a 15 sided polygon with interior angles that add to 2340 degrees.
An icosagon is a 20 sided polygon with interior angles that add to 3240 degrees.
Check out our pictures of shapes.