As R and P are mid-point of sides AB and CD so, DP and AR are equal and they are intersected at S. Hence, SR and PS are equal. Similarly, QR and PQ are equal. Also, it can be seen that AR,DP,CP,RB are equal as AD and BC are equal. So, all the four sides are equal of the parallelogram PQRS. Hence, PQRS are equal.