D 35 units squared. If you would graph it on a piece of graph paper or look at the points one side would be the difference between 10 and 3 and the other side would be the difference between 7 and 2. Then taking those totals multiple them together to get the area
Well i think you mean to simplify 42/70 which is:
(2 * 3 * 7) / (2 * 5 * 7)
= ((2 * 3 * 7) : (2 * 7)) / ((2 * 5 * 7) : (2 * 7))
= (42 : 14) / (70 : 14) = 3 / 5
The total surface area of this prism would be 120 square feet.