The document discusses medians and altitudes of triangles. It defines key terms like median, centroid, altitude and orthocenter. A median connects a vertex to the midpoint of the opposite side, while an altitude connects a vertex perpendicular to the opposite side. The centroid is the point where the medians intersect and is always inside the triangle. The orthocenter is the point where the altitudes intersect. Examples are provided to demonstrate calculating lengths and finding points related to medians, altitudes, centroids and orthocenters using given information about triangles.