Help me out thanksss !!!!

Answer:
6.244
Step-by-step explanation:
Reverse pythagreon therom since it is told that a2+b2=c2
you would have 5^2+b^2=8^2
it would end up being
25+b^2=64
go to the other side and sub 25 to 64
then you should get
b^2=39
then square it
b= 6.2449