...LINE. The point in which a line meets a plane is the foot of the line. 446. PERPENDICULAR TO A PLANE. A line is perpendicular to a plane when it is perpendicular to every line in the plane passing through its foot. The plane is then said to be perpendicular to the line....

...space intersects a plane is called the foot of the line on that plane. A straight line is said to be perpendicular to a plane when it is perpendicular to every straight line that can be drawn in the plane through its foot. Fio. 178 (a) FIG. 178 (ft) Thus, in Fig. 178 (a),...

...angles the interval joining the points. It is called the 'right bisector' plane of the points. Def. A line is 'perpendicular' to a plane, when it is perpendicular to every line which cuts it and lies in the plane. By Theorem 1, this is the case if it is perpendicular to...