Steps of construction:

Step 1: Draw AC = 8 cm.

Step 2: With A as the centre and radius = 6 cm, draw arcs on both sides.

Step 3: With C as the center and radius = 6 cm, draw arcs on both sides, intersecting the previous arcs at points B and D respectively.

Step 4: Join AB, BC, CD, DA and BD = 8.9cm.

Thus, ABCD is the required rhombus.