projectile-one of the toughest questions

A projectile passes through four vertices of a regular hexagon of side "a".(One side of the regular hexagon is on the x axis).Find its horizontal range?

Answer(So Far):

let it b ABCDEF wid AB on x-axis
as always v'll take d pt of projection as d origin O.
let C b closer 2 O dan F

take d abscissae of C as u. its ordinate will be asin60.
abscissae of D, E, F r u+a/2, u+3a/2, u+2a resp
der ordinates resp are also known

use dem in d equation of trajectory, y=xtanA(1-x/R), its easy 2 solve. just eliminate u n get d result. i didnt solvd it but i can mentally make d picture n i dnk it'll b easy.

Aliter:
find CD n as u kno d altitude of C n D u'll get a simple equation 
use d same reasonin 4 EF n it'll b solvd.............