A two dimensional shapes made from straight lines is called a **polygon**. A polygon has three or more sides.

When all the lines are the same length, and all the angles are the same, then the shape is a **regular polygon**.

A polygon has interior angles of 140º, 20º, 190º and 10º. Is it a regular polygon?

For a regular polygon, all angles have to be the same size.

Answer: No

Is it possible to have a regular polygon with only three sides?

An equilateral triangle has three sides, each of which are the same length. All the angles have the same value, 60º.

Answer: Yes - a triangle

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