Answer:
the opposite angles are equal
i.e. i) < A = <C ii) < B = < D
the opposite sides are equal that is
i)AB =CD
ii) AD= BC
the diagonals bisect each other
i) AO=OC
ii)BO=OD
the adjacent angle are supplementary . that is
i)<D + < C=180 DEGREE
ii)<A+<D=180degree
iii)<B+<C=180 degree
Explanation: