The area of the first one would be the area of the rectangle minus the area of the circle, so 18*8 - (pi*3*3). That's equal to around 115.7257 inches squared.
The area of the second one would be the area of the triangle plus the area of the semicircle, so [(4*5)/2]*[(pi*2*2)/2]. That would be 20pi, or around 62.8319 ft squared
I'm not sure about the third one. Is it a trapezoid?