The first one: The formula for a trapezoid is 1/2 h(b1+ b2) or if you split it up do 1/2 the base times the height on the triangle, then do length times width on the rectangle.
The second one: Just put and imaginary line down the sides of the H leaving the middle. The dimensions of the middle are, 3 by 4. The dimensions of the two sides are 12 by 3. Just multiply length times width, and for the two long sides... multiply by two. You should get 72 for it. Just add twelve to that, and you are good to go!