One side = 4 cm and one diagonal is 5 cm. Measure the length of other side.

In rectangle ABCD,

Let side AB = 4 cm and AC = 5 cm.

Steps of construction :

1. Draw a line segment AB = 4 cm.

2. Draw BX ⊥ AB.

3. With A as center and radius equal to 5 cm draw an arc cutting BX at C.

4. Join AC and BC. Measure BC.

5. With C and A as center and radii 4 cm and BC respectively draw arcs cutting each other at D.

6. Join AD and CD.

Hence, ABCD is the required rectangle.