Since it is a right triangle, we can apply the Pythagorean theorem:
c^2 = a^2 + b^2
Where:
c = hypotenuse = 5.83
a & b = the other 2 legs of the triangle = 5 and x
Replacing:
(5.83)^2 = 5^2 + x^2
Solve for x
34 = 25 + x^2
34 -25 = x^2
9 = x^2
√9 = x
3 = x
DF = 3