Do the diagonals of a ||gm bisect each other ?
ABCD is a parallelogram ,therefore
AB is parallel to DC and AD is parallel to BC
in triangle AOB and COD
AB=CD(opp sides of parallelogram are equal)
therefore triangle AOB= triangleCOD(ASA congurence criterian)
OA=OC & OB=OD(cpct)
hence, diagonals of parallelogram bisect each other