Arobot maneuvers itself by using a laser guidance system where the positions of reflective targets, such as at points b and c, are known. by scanning the room with a laser that emanates from point a and sensing the reflections from targets b and c, the robot may compute the direction cosines of position vectors as given below. the locations of other points, such as point d at the base of the ramp, are also known, but such locations do not have reflective targets. determine the position vector from point a to point d so that the robot may move from its current position to the base of the ramp at point d. take the coordinates of point b as (0, 0, 122) cm and point c as (250, -45, 90) cm.