Question

An___________ of a triangle is perpendicular from vertex of triangle to the opposite side.

Answer 1

We know that the altitude of the triangle is a line segment that connects the vertex of the triangle to the opposite side of the triangle, which intersects that side at exactly ${90}^o$.

We can see in the assumed triangle $△PQR$, $\overline{PM}$ is the altitude of the triangle $△PQR$.