So 1st, divide the shape into multiple other shapes.
BTW, sorry if I take long I'm trying to draw the lines on the picture.
Then, the area of a triangle in a=bh(1/2) and for trapezoids, it's (1/2(length of base 1+ length of base 2))height, so, do that for the 2 trapeziods, and do that for the triangles. I got 42.
