What I see here is a triangle sitting on top of a rectangle, and the base of the triangle is equal to the length of the rectangle. To see this, just draw a line between 'F' and 'S'. We can find the area of the triangle, hen find the area of the rectangle, and then add the two areas to get the area of the whole polygon.
The triangle: . . . The base of the triangle is 9 units long. . . . The height of the triangle is 6 units (from point 'N' down to the line FS). . . . The area of a triangle is (1/2) · (base · height)
= (1/2) · (9units · 6units)
= (1/2) · (54 units²) = 27 units².
The rectangle: . . . The length of the rectangle = 9 units. (line FS) . . . The height of the rectangle = 2 units. (line WF or line CS) . . . The area of a rectangle is
(length) · (height)
= (9units · 2units)
= 18 units²
The whole polygon: The area of the whole polygon is
