For a quadrilateral PQRS where PQ = 4 cm,QR = 6 cm, RS = 5 cm, PS = 5.5 cm. The length of PR should be less than
Since one side of a triangle cannot be greater than the sum of other 2 sides, diagonal PR must be below 10 cm which is the sum of PQ and QR. Also, it must be less than the sum of RS and PS which is 10.5 cm. Choose the lower sum.