WHY must a pentagon add up to 540° (in pictures)
Because there are now 3 triangles in a pentagon, it must add up to `3times180°=540°`
The pentagon can be made from 3 triangles.
Example 1
An equilateral pentagon will have 5 equal internal angles and would be
`540^circ/5=108^circ`
Each internal angle is 108°.
But the interior angles would still add up to 540°.
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