A pentagon is a closed 5 sided polygon.
A regular polygon has all sides equal as well as all angles equal.
°The formula to find the sum of all angles of a polygon is = (n-2) ×180
So for a pentagon, n= 5
So the sum of all the angles must be (5-2)× 180= 3 × 180 = 540.
Now as it is a pentagon, it shall have 5 vertices.
So there are 5 angles in a pentagon and all must be equal.
Hence each interior angle must be 540/5 = 108
So for a regular polygon with 5 sides must have each interior angle = 108
