Answer:
5
Step-by-step explanation:
We know that 13 is the hypotenuse. With this we can use the Pythagorean Theorem to solve this problem.
Let the third side be x.
13^2=12^2+x^2
169=144+x^2
169-144=x^2
25=x^2
x=5
Solved.
B. ASA
FGH = IHG
Please correct me if I'm wrong!! :)