If the perpendicular distance of a point P from the X-axis is 5 units and the foot of the perpendicular lies on the negative direction of X-axis, then find the y-coordinate of point P.

We know that the perpendicular distance of a point from the X-axis gives y-coordinate of that point. Here, foot of perpendicular lies on the negative direction of X-axis, so perpendicular distance can be measure from II quadrant or III quadrant. Hence, the point P has y-coordinate = 5 or-5.