[Hint. Produce AD to E such that AD = DE and join C and E.]
OR
Prove that the sum of any two sides of a triangle is greater than twice the length of median drawn to the third side.
Prove that the sum of the three sides of a triangle is greater than the sum of its three medians.
OR
Prove that the perimeter of a triangle is greater than the sum of its three medians.
From example 8 above,
AB + AC > 2AD ...(1)
Similarly,
BC + BA > 2BE ...(2)
| ∵ BE is a median
and CA + CB > 2CF ...(3)
| ∵ CF is a median
Adding (1), (2) and (3), we get
2(AB + BC + CA) > 2(AD + BE + CF)
⇒ AB + BC + CA > AD + BE + CF
⇒ Sum of the three sides of triangle ABC > Sum of the three medians of triangle ABC.