Answer:
49
Step-by-step explanation:
The sum is of n and 14 can be written as:
n+14=72
There are no "of the following" listed, but when you multiply a length by 2/3, you're indicating that you are only "using" 2/3 of that length, which is smaller by a third. Regardless of what your original lengths of the diagonals are, the area is going to be smaller. By 2/3, to be exact.