The altitude of a right triangle to the hypotenuse is the geometric mean (mean proportional) of the two segments of the hypotenuse:
$$h^{2}=pq \Rightarrow h=\sqrt{pq}$$
It states that the altitude to the hypotenuse is the geometric mean of the two segments of the hypotenuse.
They represent the two segments into which the altitude divides the hypotenuse.
It is used in right triangle geometry problems involving altitudes, hypotenuse segments, and proportional relationships.