A polygon is just a fancy name for any flat shape (also known as a 2-dimensional shape) which is made by drawing straight lines which all join together.
Number of Sides Name of Polygon How to remember the name
3 Triangle The name says that the shape has 3 angles (Tri is an old word for 3) - it also has 3 sides.
4 Quadrilateral If someone gives birth to "Quads" - they have 4 babies - this shape has 4 sides
5 Pentagon The number 5 looks like the letter S, put 5 in front of Pent and it looks like Spent - this shape has 5 sides
6 Hexagon The word Six ends with the letter x and so does Hex (another old word which means six) - this shape has 6 sides
8 Octagon An octopus has 8 legs - this shape has 8 sides
10 Decagon The word Decompress has 10 letters and begins with Dec - this shape has 10 sides