4) Given: PQRS is a parallelogram , PM=1/3PS , RN=1/3QR
To prove:PNRM is a parallelogram
Construction : join PN and MR
Proof: PS=QR (opposite sides equal)
1/3PS=1/3QR
PM=RN ..(i)
PM||RN ..(ii)
From (i) and (ii) we get a quadrilateral with opposite sides both equal and parallel
Thus PNRM is a parallelogram
Hence proved