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°`
The square can be made from 2 triangles.
If you push over only one side of the square, the square's interior angles still add up to 360°.
Again, we know this because this new shape is still made up of two triangles.
And 2 triangles are `2times180=360°`