Construct a quadrilateral PQRS in which PQ = 4.2 cm,

Steps of construction:

Step 1: Take $P Q=4.2 \mathrm{~cm}$

Step 2: Make $\angle X P Q=120^{\circ}, \angle Y Q P=60^{\circ}$

Step 3: Cut an arc of length 5 cm from point Q. Name that point as R.

Step 4: From P, make an arc of length 6 cm. Name that point as S.

Step 5: Join P and S.

Thus, PQRS is a quadrilateral.