What is a polygon?

A polygon is a two-dimensional shape with straight sides that join up to enclose a space, with no gaps and no curves. Polygons are named by their number of sides: three sides is a triangle, four a quadrilateral, five a pentagon, six a hexagon. A shape with any curved side, like a circle, is not a polygon.

Examples

• A triangle is a polygon with 3 sides.
• A pentagon has 5 sides; a hexagon has 6.
• A circle is not a polygon because it is curved.

Quick facts

• A regular polygon has all sides and all angles equal.
• A polygon has the same number of corners (vertices) as sides.