Area of a semicircle = \(\frac{1}{2}\pi r^2\).<br><br>From the figure, the diameter is shown. The radius \(r = 21\) cm.<br><br>Using \(\pi = \frac{22}{7}\):<br>\(\frac{1}{2} \times \frac{22}{7} \times 21^2 = \frac{1}{2} \times \frac{22}{7} \times 441 = 693\) cm&sup2;.<br><br>Final Answer: 693 cm&sup2;