Perpendicular and oblique

A line is perpendicular to a plane if it forms a right angle with every line in the plane that passes through the point of intersection. If a line meets a plane but is not perpendicular, it is called oblique.

Important properties

• The shortest distance from a point to a plane is along the perpendicular.

• The foot of the perpendicular from a point to a plane is the closest point on the plane to the given point.

• Oblique segments from a point to a plane are longer than the perpendicular segment.

• Oblique segments from a point to a plane that have equal projections onto the plane are equal in length.