Math
Hexagon
Shapes for kids: Hexagons. The hexagon is a six sided polygon. Each side must be closed and the shape not only needs six sides to qualify as a hexagon, but it must have six angles.
N-gon
These segments are called its edges or sides, and the points where two edges meet are the polygon's vertices (singular: vertex) or corners. The interior of the polygon is sometimes called its body. An n-gon is a polygon with n sides; for example, a triangle is a 3-gon.
Nonagon
You may not realize it, but a square is a regular polygon. More specifically, a square is a regular quadrilateral, or four-sided shape. It has four equal sides and four right angles, each measuring 90 degrees. A regular nonagon is a nine-sided shape with equal sides and equal angles of 140 degrees each.
Apothem
A line from the center of a regular polygon at right angles to any of its sides.
Decagon
A polygon is a closed, 2-dimensional shape with straight sides. This means circles and ovals don't count. A decagon is a 10-sided polygon. It also has ten vertices - which is where the sides meet - and angles.
Heptagon
A polygon is an enclosed two-dimensional shape with straight sides. This includes triangles, quadrilaterals, pentagons, etc but not circles or ovals. A heptagon is a seven-sided polygon. Along with seven sides, a heptagon has seven vertices and angles.
Center of a polygon
Definition: The point inside a regular polygon that is equidistant from each vertex. Try this Adjust the number of sides of the polygon below, or drag a vertex to note the center point of the polygon.
Octagon
Image result for octagon shape An octagon is a geometrical shape that contains eight sides and eight angles. Octagons must have straight sides that connect; they cannot be curved or disconnected.
Pentagon
Image result for pentagon shape In geometry, a pentagon (from the Greek πέντε pente and γωνία gonia, meaning five and angle) is any five-sided polygon or 5-gon. The sum of the internal angles in a simple pentagon is 540°.
Regular Polygon
Polygon. A polygon is a plane shape (two-dimensional) with straight sides. Examples include triangles, quadrilaterals, pentagons, hexagons and so on.