First split it up into polygons which are easy to find the area of
you could do it this way
Area if triangle ABC + Area triangle AFG ( where G is a point 3 units to left of F) + area of trapezoid GEDC
=1/2 * 3 * 9 + 1/2 * 3 * 3 + 1/2 * ( 7 + 6) * 6
= 13.5 + 4.5 + 1/2 * 78
= 18 + 39
= 57
