Using the Pythagorean theorem:
a^2 + b^2 = c^2 ( a and b are the sides and c is the diagonal)
59.5^2 + b^2 = 70^2
Simplify:
3540.25 + b^2 = 4900
Subtract 3540.25 from both sides:
b^2 = 1359.75
Take the square root of both sides:
b = 36.874
Rounded to the nearest tenth = 36.9 inches.
