4 1/3 would be the answer. Hope that helps you!
It's a parallelogram so if one angle is 90 degrees they all will be because of transverse angles and all that good stuff.
So we're given the diagonal of a rectangle and one side and we're asked to find the other. The diagonal of a rectangle is the hypotenuse of the right triangle whose legs are the sides of the rectangle. So this is a Pythagorean Theorem question in disguise:




Answer: 140 cm
I don't recall seeing this Pythagorean Triple before.
90% out of 105% which would be 0.85
70-40= 30
30/2 = 15
40/2= 20
15 x 20 = 300