Construct a quadrilateral ABCD in which AB = 4.2 cm,

Steps of construction:

Step 1: Draw $\mathrm{AB}=4.2 \mathrm{~cm}$.

Step 2: With A as the centre and radius equal to $8 \mathrm{~cm}$, draw an arc.

Step 3: With B as the centre and radius equal to $6 \mathrm{~cm}$, draw another arc, cutting the previous arc at C.

Step 4: Join BC.

Step 5: With A as the centre and radius equal to $5 \mathrm{~cm}$, draw an arc.

Step 6: With C as the centre and radius equal to $5.2 \mathrm{~cm}$, draw another arc, cutting the previous arc at D.

Step 7: Join AD and CD.

Thus, ABCD is the required quadrilateral.