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I am trying to prove that the following triangles are similar.

enter image description here

Following information is given in this regard:

AB, AC & median AD of triangle ABC are respectively proportional to PQ, PR & median PM of triangle PQR.

 AB/PQ=AC/PR=AD/PM=x (given)-----(1) 

To prove that these two triangles are similar, I am trying to prove: BC/QR=x (S-S-S similarity condition)

I proceeded like this:

 AB+AC+BC=P1, PQ+PR+QR=P2-------------(2) 

from (1), these equations become:

 xPQ + xPR +BC=P1, PQ+PR+QR=P2------ -(3)   =>BC=P1- x(PQ+PR), QR=P2-(PQ+PR)-----(4)  

From (4)

 BC/QR= (P1-x(PQ+PR))/(P2-(PQ+PR))-----(5) 

In the above method so far I have not been able to use the information:

          AD/PM=x--------------------- (6)     

How do I proceed now to prove BC/QR=x?

I understand that there can be other methods to prove that the two triangles are similar, but I am particularly interested in proving this using Eqn (3) (and possibly Eqn (6), and some other property). The thing is Eqn (3) must be used and it should not be made redundant information.

  • 0
    I do not think a proof will succeed without using some geometric property of the median that goes beyond the fact that it divides a side into two equal parts.2012-11-27
  • 0
    Other properties can be used but Eqn-3 must be used, as I updated in my question2012-11-27

2 Answers 2