Answer:
2304
Step-by-step explanation:(this is how I do it so sorry if people do it a different way.) so that it's easier for me I like to double the prism so it makes a square. then you take the length and with and multiply them together. that multiply what you just got by the width "length at the top". then divide your answer by 2.
D) 12 would NOT be a possible length for the third side because the sum of the 2 shorter legs should be greater than the longest leg.