A parallelogram has adjacent sides of 78 inches and 90 inches, and the angles between them is 35 degrees. Find the length of each of the diagonals.

the two diagonals d1 and d2 can be found using the law of cosines:

d1^2 = 78^2 + 90^2 - 2(78)(90)cos35°
d2^2 = 78^2 + 90^2 - 2(78)(90)cos145°
= 78^2 + 90^2 + 2(78)(90)cos35°