Page 58 - Key Stage 3 Geometry

4 Irregular Polygons

You may not realise it but you see irregular polygons

every day – for example the

letter T is an octagon as you can
see from the diagram on the

left. When we say irregular, we
mean the sides are not the all

the same length as you can see

in the letter T. The letter E is dodecagon – how many
sides has it got? When looking at irregular polygons

we are interested in the number of sides, their length
and the internal angles.

4.1 Triangle

Triangles fall into one of four categories as shown
below.

Equilateral Isosceles Right Irregular
angled

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