In a△ABC, ADis median. Show that AB+BC+AC>2AD
Given, ADis median in △ABC
To prove, AB+BC+AC>2AD
Let △ABCwhere ADis a median
In∆ABD, by the property of the triangle we have
AB+BD>AD.......(i)
In∆ACD, by the property of the triangle we have
AC+DC>AD......(ii)
Adding (i)and(ii) we get
AB+BD+AC+DC>AD+ADAB+BC+AC>2AD(sinceBD+DC=BC)
Hence, AB+BC+AC>2AD proved.
In a triangle ABC, AB=AC. Show that the altitude AD is median also.