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.
did you make a sketch?
let the shorter diagonal be x
by the cosine law:
x^2 = 78^2 + 90^2 - 2(78)(90)cos35°
...
x = 51.8 to the nearest tenth
let the longer diagonal by y
y^2 = 78^2 + 60^2 - 2(78)(90)cos145°
etc