To Prove: PM < PN.
Proof: In ∆PMN,
∠M = 90°
∴ ∠N is an acute angle.
| Angle sum property of a triangle
∴ ∠M > ∠N
∴ PN > PM
| Side opposite to greater angle is greater
⇒ PM < PN.
[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.