A pentagon is a polygon with 5 vertices. A polygon can be rotated 360 degrees in total. Since this shape has 5 vertices, it can be rotated on every vertex to get the same figure, or in other words, it being mapped onto itself. Therefore, 360 degrees divided by 5 vertices is 72 degrees.
You use the formula Interest=principle (rate) time or i=prt. If you use that formula to solve, your answer will be 3,500. After five years, the balance will be $3,500.
