An equilateral triangle Δ ABC with sides 12 cm has a point D on one of its sides such that BD = \(BC\over6\). The length of AD is:
1
\(\sqrt{124}\) cm
2
12 cm
3
22 cm
4
\(\sqrt{424}\) cm
An equilateral triangle Δ ABC with sides 12 cm has a point D on one of its sides such that BD = \(BC\over6\). The length of AD is: