We can draw this as:
We can use the Pythagorean theorem to find the length of the cable, as it is the hypotenuse of a right triangle:
[tex]\begin{gathered} c^2=7^2+8^2 \\ c^2=49+64 \\ c^2=113 \\ c=\sqrt[]{113} \\ c\approx10.63 \end{gathered}[/tex]Answer: the cable length is 10.63 m.