How do you know if the problem is a solution or not a solution

I’m on question 7 it says a covered water tank is in the shape of a cylinder the tank has a 28 inch diameter and a height of 66 inches to the nearest square inch what is the surface area of the water tank

Ineed to know the ordered pairs for this equation i need the answer quick because it’s a timed test

Why is x= 4 a solution to the proportion 14/x 56/1 6