Hello!
To solve this we can use the Pythagorean Theorem, which is a²+b²=c², where a and b represent the legs, and c represents the hypotenuse.
36+81=117
√117≈10.82
Now we find the values of each of our answers and see which one matches.
3√13≈10.82
We can see that our correct answer is 3√13.
I hope this helps!