Noshi ordered a new desk for her office. The desk came in two parts, each shaped like a trapezoid. The height of both part A and part B is 3 feet. Noshi wants to be sure the desk will fit in her office so she calculates the area of the desk. What is the total area of the desk?

Imagine you're cutting off all of the slanted sides, there would be 3. Now since there's 4 feet on one side and 9 on the other when you cut off the edges they have side which are 3 feet (the end number) and 2.5 (9-4=5/2=2.5) now since you have three pieces like this, so put 2 together and you get a shape which is 3feet by 2.5 feet. The area of this is 3*2.5 which is 7.5, cut that in half for the third piece and you get 3.25, added together that's 10.75 squared feet. Now don't forget the 3 by 4 and 3 by 5 pieces. That would be a total of 27 (3*4=12 3*5=15) 27+10.75=37.75 squared feet.
Let me know if I made a mistake any where :)