Hi all I was wondering if anyone could point me in the right direction with this problem.

lighthouse L located at (90, -30) equation of the line of travel of the boat is $\displaystyle y=-\frac{1}{3}x+33\frac{1}{3}$

Let d kilometres be the distance between the location of the boat at parameter value t and the lighthouse L. Find an expression for d^2 in terms of t.