Chapter 11, Problem 11.15PE

(Area of a convex polygon) A polygon is convex if it contains any line segments that connects two points of the polygon. Write a program that prompts the user to enter the number of points in a convex polygon, enter the points clockwise, then displays the area of the polygon. For the formula for computing the area of a polygon, see http://www.mathwords.eom/a/area_convex_polygon.htm. Here is a sample run of the program:

  Enter the number of points: 7

  Enter the coordinates of the points:

  –12 0 –8.5 10 0 11.4 5.5 7.8 6 -5.5 0 –7 –3.5 –13.5

  The total area is 292.575