Question 891775
Assuming you're dealing with a right triangle. I'm also assuming the legs are 5 and 12 and the hypotenuse is unknown.



x^2 + y^2 = z^2


5^2 + 12^2 = z^2


25 + 144 = z^2


169 = z^2


z^2 = 169


z = sqrt(169)


z = 13



So the hypotenuse AC is 13 units long.