The centroid of a triangle is the point where its medians intersect. It works by constructing the perpendicular bisectors of any two sides to find their midpoints. Then the medians are drawn, which intersect at the centroid.
The orthocenter is the point where all three altitudes of the triangle intersect. An altitude is a line which passes through a vertex of the triangle and is perpendicular to the opposite side. There are therefore three altitudes in a triangle.
