Respuesta :
"Break into triangles, then add. In the figure on the right, the polygon can be broken up into triangles by drawing all the diagonals from one of the vertices. If you knowenough sides and angles to find the area of each, then you can simply add them up to find the total." -www.mathopenref.com/polygonirregulararea.html
By adding all the sides of the polygon and then divide of the sides.