Question

y varies directly as the square of x. When x = 1, y = 3. What is the value of y when x = 3?

Answer 1

If x=1, then x^2=1, and since x^2 and y are in direct proportion, y/x^2 is always equal to 3/1=3.

If x is 3, x^2 is 9, so y is thus 9*3=27.