will mark brainliest. only answer if you know it. random answers will be reported.

Answer:
b = 17.55
Step-by-step explanation:
a^2 + b^2 = c^2
4^2 + b^2 = 18^2
16 + b^2 = 324
-16 -16
b^2 = 308
square root them
b = 17.55
let me know if it is correct!
Step-by-step explanation:
4^2 + h^2 = 18^2
16 +h^2 = 324
h^2 = 308
h = √308
h = 17.5499 ft