Question

A regular polygon has an interior angle of 105 how many sides does it have?

Answer 1

Number of sides = 360 / (180 -one interior angle)
Number of sides = 360 / (180 -105)
Number of sides = 360 / 75
Number of Sides = 4.8

Perhaps you made a typo in your question?

A polygon with an interior angle of 108 degrees has five sides.
It's a pentagon.