\(\pi\) = \(\frac{22}{7}\), Diameter D = 42m Area of a circle = \(\frac{\pi D^2}{4}\) when a diameter is given area of a semicircle \(\frac{\pi D^2}{4}\) x \(\frac{1}{2}\) = \(\frac{22}{7}\) x \(\frac{5541.7694}{4}\) x \(\frac{1}{2}\) = \(\frac{11}{7} \times 441\) = 693m\(^{2}\)