The equation of the parabola is: 169 {(x-1)2 + (y-3)2 } = (5x - 12y + 17)2
Now this equation of the parabola can be given as: (x-1)2 + (y-3)2 = { (5x - 12y + 17)/(5)2 + (12)2 }2
This is nothing but form of: SP = PM form where S = Focus of parabola and P = any point on parabola. and M = perpendicular from point "P" to "Directrix".
Therefore,from above equation: Focus S = (1,3) and directrix = 5x - 12y + 17 = 0 Therefore, Let Z be the intercept of directrix and X-axis. Then SZ = perpenicular distance of focus S from directrix = 2a