In an equilateral triangle ABC if AD ⊥ BC, then
A. 2AB2 = 3AD2
B. 4AB2 = 3AD2
C. 3AB2 = 4AD2
D. 3AB2 = 2AD2
The correct option is (C) 3AB2 = 4AD2.
∆ABC is an equilateral triangle and AD⊥BC.
In ∆ABD, applying Pythagoras theorem, we get