If in an equilateral triangle △ABC, AD is perpendicular to BC, then AD2=
In ΔABC, AD⊥BC.
then, AC2=AD2+CD2 [By Pythagorus Theorem]
⇒AD2=AC2−CD2
⇒AD2=BC2−CD2 [since, AC=BC]
⇒AD2=(2CD)2−CD2 [since, BC=2CD]
⇒AD2=3CD2
If △ABC is an equilateral triangle such that AD is perpendicular to BC, then AD2=