Answer:
x = 14.25
Step-by-step explanation:
Start with a^2 + b^2 = c^2
a = 11
b = x
c = 18
plug in and solve
11^2 + x^2 = 18^2
121 + x^2 = 324 - Simplify
x^2 = 203 - subtract 121 from both sides
x = 14.247 rounds to 14.25 - square root on both sides