WHY must a square add up to 360° (in pictures)

Because there are now 2 triangles in the square, each equaling `180^@`, it must add up to `2times180°=360°`

A square is 2 triangles so 2 x 180 is 360 degrees

The square can be made from 2 triangles.

Example 1

If you push over only one side of the square, the square's interior angles still add up to 360°.

`90°+90°+110°+70°=360°`

Again, we know this because this new shape is still made up of two triangles.

There are 2 triangles in this shape so the interior angles totals 360 degrees

And 2 triangles are `2times180=360°`