In an equilateral triangle ABC,D is point on side BC such that BD=1/3 BC ,prove that 9AD^2=7AB^2

In an equilateral triangle ABC,D is point on side BC such that BD=1/3

1.	In an equilateral triangle ABC,D is point on side BC such that BD=1/3 BC ,prove that 9AD^2=7AB^2
Answer» Take LHS (AD^2)and solve Consider every side as \'a \'unit and then apply Pythagoras theorem