Construct a quadrilateral ABCD in which AB = BC = 3.5 cm,

Steps of construction:

Step 1: Draw $A B=3.5 \mathrm{~cm}$.

Step 2: Make $\angle A B C=120^{\circ}$.

Step 3: With B as the centre, draw an $\operatorname{arc} 3.5 \mathrm{~cm}$ and name that point $C$.

Step 4: With $C$ as the centre, draw an arc $5.2 \mathrm{~cm}$.

Step 5: With $A$ as the centre, draw another $\operatorname{arc} 5.2 \mathrm{~cm}$, cutting the previous arc at $D$.

Step 6: Join $C D$ and $A D$.

Thus, $A B C D$ is the required quadrilateral.