consider 2 ll lines be y=f n y=-(1-f) one f units away frm x axis n ll to it let Q be (0,f) lying on line y=f n let P be (p,o) lying on x axis, let  x be the angle bt y axis n QR  (let R(r,f-1)

 nw tanx=r n tan(60+x)=p/f find tanx n 1+r^2=side^2=p^2+f^2

  we know dat r=tanx compute side