Question 85161
The right angle triangle formula is {{{A^2+B^2=C^2}}}

because c= hypotenuse
and you have a side a/b
you can isolate the other side by making the equation {{{A^2=C^2-B^2}}}

by quaring the information you have you can fill in the equation

{{{A^2=sqrt(58)^2-7^2}}}

and by square routing the answer you find a

A=3

so your third side is equal to 3