If each angle of a regular polygon measures 140 degrees, how many sides does it have?

Answer 1

Are these external angles or internal angles?

I will assume that they are internal angles. That would make the external angles 40 degrees each. Since the external angles must add up to 360, the number of sides, and angles is 360/40 = 9.

Answer 2

http://www.coolmath.com/reference/polygons.html