Draw a segment from F to S.
Now you have broken up the polygon into rectangle FSCW with length 9 units and width 2 units, and triangle FSN with base 9 units and height 6 units. The area of the polygon is the sum of the areas of the rectangle and the triangle.
A = LW + (bh)/2
A = (9 u)(2 u) + (9 u)(6 u)/2
A = 18 u^2 + 27 u^2
A = 45 u^2
