Answer: x = 24
Step-by-step explanation:
Use the Pythagorean Theorem:
[tex]x^{2}+18^{2}=30^{2} \\x^{2} = 30^{2}-18^{2}\\x=\sqrt{30^{2}-18^{2}}=\sqrt{900-324}=\sqrt{576} =24[/tex]
