# Angles in polygons

- Author:
- Lizzie Robson

## Triangles

What do you notice about the triangles angles above? Move the triangle around, do the angles change?

## Squares

What do the angles in a square add up to make? Hint: you can add them up if you are unsure

- A
- B
- C

Notice the square above can be split into 2 triangles. What do the angles inside a triangle add up to make?

- A
- B
- C

This time you have only been given one angle inside the pentagon. Like the shapes above it is regular which means all the angles are the same size. What does this mean the angles inside total?

- A
- B
- C
- D

The angle inside a shape is called the **interior angle**. For all the polygons above, when you move the points do the interior angles of the shape change?

**exterior angle**. You can work out the exterior angle by doing 360 divided by how many sides there are. For example in a pentagon there are 5 sides so the exterior angle is

## Can you work out the exterior angles of the shapes above?

What is the exterior angle of the yellow shape? Can you name this shape?

What is the exterior angle of the red shape? Can you name this shape?

What is the exterior angle of the blue shape? Can you name this shape?

## Fill in the table below by using your formula

**Hint: Remember your formula..**Exterior angle = Interior angle = 180

^{o}- exterior angle Total Interior angles = Interior angle x sides

__Think about where these shapes are used in real life.. For example: A football pitch is a quadrilateral. A 50 pence is a heptagon. Write these down on a piece of paper so we can share our great ideas at the end.__

**Extension Task:**