SAT Linear equations in one variable Question

For a certain type of rope, the equation $y=900a{x}^2$ , where a is a constant, gives the estimated breaking strength y, in pounds, of a rope with a circumference of x inches. Based on this equation, if a rope of this type has a circumference of 1.75 inches, it has an estimated breaking strength of 3,858.75 pounds. What is the estimated breaking strength, in pounds, of a rope of this type that has a circumference of 3.50 inches?