# Foot of a perpendicular

For a given line $l$ and point $P$, if we draw a line through $P$ perpendicular to $l$, then this line will intersect $l$ at a point $Q$. The point $Q$ is called the foot of the perpendicular line.

Similarly, if we draw an altitude of a triangle or another figure, the point where the altitude meets the side to which it is perpendicular is called the foot of the altitude.