can someone help me please asap!

Answer: 24 ft
Step-by-step explanation:
We use Pythagoras' Theorem.
So, Hypotenuse^2 = Side A^2 + Side B ^2
=> 30^2 = 18^2 + b^2
=> b^2 = 30^2 - 18^2
=> [tex]\sqrt{b^{2} }[/tex] = [tex]\sqrt{30^{2} - 18^{2} }[/tex]
=> b = [tex]\sqrt{576}[/tex]
=> b = 24 ft