A regular pentagon is rotated counterclockwise about its center until it coincides with its original position. If the pentagon is rotated by an obtuse angle, then what is the obtuse angle?
+40 A pentagon has 5 sides, therefore its rotational symmetry is 72 degrees, but that is not an obtuse angle so 2*72 is 144, which is an obtuse angle so therefore the obtuse angle is 144 degrees
