@ vaibhav
u need to directly apply the formula over here ,
like L= AB COS 30 DEGREE
and the ques seems incomplete as u have not mentioned the mass of three particle present in the equilateral triangle ,
and also L needs to be of some value
lets take L = 0.5 m
so, L = AB COS 30
= 0.5 * ROOT3/2
= 0.43 M
here we need the masses of three particle to proceed further
use the formula
X = ma x1 + mbx2 + mcx3 / ma+mb+mc
then proceed on
ALL THE BEST ..
