Mammoth Memory


Nonagon – a polygon with 9 sides

NiNe of them

Nine of them sounds like nonagon so makes this easy to remember.

A nonagon has 9 sides 

If none are gone (nonagon) then a cat has nine lives. 

Example 1

This is a regular nonagon  

A regular nonagon has nine sides of equal length.


Example 2

A nonagon has a total of 1260 degrees internally

If you add up all the internal angles of a regular convex nonagon you will get 1260°.


Example 3

A nonagon has 8 vertices where they have 140 degree angles individually  

A regular convex nonagon has an internal angle of 140° between each side.


Example 4

This shape is a nonagon

This shape looks like a Y but as it has 9 sides, it’s a nonagon.


Example 5

This shape is an irregular nonagon 

Irregular nonagons such as this one may not have a symmetrical shape but will still have nine sides.

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