How do i prove that the three medians of a triangle are concurrent at a point called centroid?

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juicilysv · Accepted Answer

Consider triangle ABC (below) with medians AD and BE.Construct two points H and G as the midpoints of segments DC and BD, respectively.It is now necessary to construct appropriate parallel lines so that we may apply the mentioned corollary. Construct four parallel lines 1, l2, l3, and l4 each parallel to line l, the line containing median AD, through pointsB,G,H, and C, respectivey. The transversal line BC has congruent segments, BG,GD,DG,HC.Since E is the midpoint of AC, l3 intersects AC at the point E by the above corollary, using AC as the transversal.In addition, using BE as a transversal, we have that , BF = FR = RE.Thus the medians AD and BE intersect at R (the centroid!), a point that is two-thirds of the way from B to E, so BR = (2/3)BE.Repeating the process using the other two pairs of medians gives the desired concurrent point R, which is the centroid of triangle.

How do i prove that the three medians of a triangle are concurrent at a point called centroid?

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