Answer:
[tex]\sqrt{39}[/tex]
Step-by-step explanation:
I think the answer choices were supposed to be:
[tex]\sqrt{3} , \sqrt{6} , \sqrt{39} , \sqrt{89}[/tex]
Pythagorean Theorem: a²+b²=c²
5²+b²=8²
25+b²=64
Subtract 25 from both sides
b²=39
Square root both sides
b=[tex]\sqrt{39}[/tex]
Our answer is [tex]\sqrt{39}[/tex]
