Here's how you would change the formula for the different polygons below. You can even try drawing the shapes out yourself and practise partitioning them into the correct amount of triangles.

Two-dimensional (2D) shapes are completely flat. They have two dimensions – length and width. A polygon is a closed 2D shape with straight sides that meet at vertices. Polygons can be regular or ...

Here's how you would change the formula for the different polygons below. You can even try drawing the shapes out yourself and practise partitioning them into the correct amount of triangles.

2D shapes can be found printed in a book or you can draw them on a piece of paper ... some common 2D shapes by their properties. A polygon is a 2D shape with straight sides that meet at vertices.