In order for us to know the answer, we are going to apply pythagorean theorem here since the rectangle has been divided using a cross bar. The legs of the triangle would be 3 feet and 5 feet. Pythagorean theorem is a2 + b2 = c2.
3^2 + 5^2 = c2
9 + 25 = c2
34 = c2 (now square this one)
So c = 5.83.
Therefore, the length of one crossbar is 5.83 feet. Hope this helps.