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Names of Polygons

### 6 sides- Hexagon

7 sides- Heptagon

8 sides- Octagaon

9 sides- Nonagon

10 sides- Decagon

### Triangle

A three-sided polygon. The sum of the angles of a triangle is 180 degrees.

Examples:

### Equilateral Triangleor Equiangular Triangle

A triangle having all three sides of equal length. The angles of an equilateral triangle all measure 60 degrees.

Examples:

A four-sided polygon. The sum of the angles of a quadrilateral is 360 degrees.

Examples:

### Pentagon

A five-sided polygon. The sum of the angles of a pentagon is 540 degrees.

Examples:

 A regular pentagon: An irregular pentagon:

### Hexagon

A six-sided polygon. The sum of the angles of a hexagon is 720 degrees.

Examples:

 A regular hexagon: An irregular hexagon:

### Heptagon

A seven-sided polygon. The sum of the angles of a heptagon is 900 degrees.

Examples:

 A regular heptagon: An irregular heptagon:

### Octagon

An eight-sided polygon. The sum of the angles of an octagon is 1080 degrees.

Examples:

 A regular octagon: An irregular octagon:

### Nonagon

A nine-sided polygon. The sum of the angles of a nonagon is 1260 degrees.

Examples:

 A regular nonagon: An irregular nonagon:

### Decagon

A ten-sided polygon. The sum of the angles of a decagon is 1440 degrees.

Examples:

A regular decagon

### Undecagon

An eleven-sided polygon.

Dodecagon

A tweleve-sided polygon

An irregular decagon: