As a first step we are going to operate the square power:
square power to a radical, it's equal to the same number into the radical.
[tex]\begin{gathered} (\frac{1}{5})^2+(\frac{1}{7})^2=(\sqrt[]{\frac{74}{35}})^2 \\ \frac{1}{25}+\frac{1}{49}=\frac{74}{35} \\ \frac{74}{1225}=\frac{74}{35} \\ \text{Although this statement is not true.} \end{gathered}[/tex]If the sum of the two shorter sides (1/25 and 1/49) is greater that the length of the third side (74/35) then you can form a triangle, in this case this numbers cannot form a triangle because they don't sum more than the third side.