Given: In ΔABC
(1) D is the midpoint of the side BC
(2) E is the midpoint of the side BD
(3) O is the midpoint of the side AE
Proof: We know that the median of a triangle divides the triangle into two triangles of equal area.
Since AD and AE are the medians of ΔABC and ΔABD respectively. And OB is the median of ΔABE
Hence we have proved that