# WHY must a heptagon add up to 900° (in pictures)

Because there are now 5 triangles in a heptagon and it must add up to `5times180°=900°`.

The heptagon can be made from 5 triangles.

**Example 1**

An equilateral heptagon will have 7 equal internal angles and would be

`900^circ/7=128.57^circ`

Each internal angle is 128.57°.

But the interior angles would still add up to 900°.