EXPLANATION PLEASE AND ILL BRAINLIEST YOU

Answer:
blank 1: 24
Step-by-step explanation:
According to Pythagoras' Theorem, in a right-angled triangle,
(side 1)² +(side 2)²= (hypotenuse)²
Applying Pythagoras' Theorem,
x² +18²= 30²
x² +324= 900
x²= 900 -324 (-324 on both sides)
x²= 576
[tex]x = \sqrt{576} [/tex]
x= 24 ft