Problema Solution
A side and a diagonal of a parallelogram are 12 inches and 19 inches respectively. The angle between the diagonals, opposite the given side, is 124 degrees. find the length of the other diagonal.
Answer provided by our tutors
Let length of other diagonal be 2x
By cos formula cos 124= (x 2 + 9.5 2 - 12 2 )/2(9.5)x
x 2 + 10.625 x - 53.75 = 0
x =( - 10.625 ± (10.625 2 - 4(53.75)) 1/2 )/2 = 3.741
Length of other diagonal = 2x = 7.482 inch