The given segment has the slope m == = = . The middle point of the given segment is (1,1). So, we need to write the equation of the line perpendicular to the given segment and passing through the point (1,1). The perpendicular line has the slope and its equation is y - 1 = , or 3y - 3 = 4x - 4, or 3y - 4x = -1.