Can someone help me with this i don't understand tyy

Question b: the longest side is b (the one not labelled)
Step by step :
A^2+B^2=C^2
8 squared =64
6 squared=36
36+63=100
Square root of 100=10 so the longest side is b

I’m not much help but, I finished this unit a couple months ago, and I think b is the line that’s 6 because it’s across from the 90 degree angle, but my teacher explained it really bad, hope this helped a little.