One side = 68 / 4 = 17
1/2 the length of the known diagonal = 16
1/2 the length of the unknown diagonal = sqrt [ 17^2 - 16^2 ] = sqrt [ 289 - 256] = sqrt 33
Area of rhombus = product of diagonals / 2 =
(2 * 16) ( 2 * sqrt 33) / 2 =
32*sqrt(33) units^2