A median 
of a triangle 
is the Cevian from one of its vertices 
to the midpoint 
of the opposite side. The three medians of any triangle
are concurrent (Casey 1888, p. 3), meeting in
the triangle centroid (Durell 1928) 
, which has trilinear
coordinates 
.
In addition, the medians of a triangle divide one another
in the ratio 2:1 (Casey 1888, p. 3). A median also bisects the area
of a triangle.
Let 
denote the length of the median of the 
th side 
. Then
 |  |  |
(1)
|
 |  |  |
(2)
|
(Casey 1888, p. 23; Johnson 1929, p. 68). The area of a triangle can be expressed in terms of the medians by
 |
(3)
|
where
 |
(4)
|
