Geometry: Polygons

Problem : A regular polygon has 5 diagonals. What are the measures of its exterior angles?

Problem : A polygon has 7 vertices. How many diagonals does it have?

Problem : If a polygon has n sides, how many diagonals can be drawn from a given vertex?

Problem : In the figure below, are angles x and y complementary?

Problem : For what kind of polygon is the sum of the exterior angles equal to the sum of the interior angles?