We can use pythagorean theorem:
a^2 + b^2 = c^2
4 + 9 = c^2
13 = c^2
sqrt of 13 = c
Hope this helps!
The question doesn't seem specific enough. If there are options, please list.
Answer:

Step-by-step explanation:
If x is inversely porportionaly to y, then for some constant k,

Since y is 4 when x = 18, k is equal to 4*18=72, so the equation is:

24 inches hope this helps