(setq C (cal "pld(O,O+nor(A,B,O),L)"))
It was Excellent !!! Thanks I Used it as :
(defun c:a ()
(setvar "osmode" 12287)
(setq p1 (getpoint "\n Base Point : "))
(setvar "autosnap" 39)
(setvar "orthomode" 0)
(setq p2 (getpoint " First Hand : " p1))
(grdraw p1 p2 2 1)
(setq p3 (getpoint " Second Hand : " p1))
(grdraw p1 p3 3 1)
(cond ((not c:cal) (arxload "geomcal")))
(setq po (cal "pld(p1,p1+nor(p2,p3,p1),1.0)"))
(print (acet-geom-unit-vector p1 po))
(command "3dpoly" p1 p2 p3 p1 po "close")
(princ)
)