Question

Find the shaded area

Answer 1

88.85 Sq m

Explanation:

For rectangle:

Length = 18 - 7.8 = 10.2 m

Width = 7.8 m

For both semicircular arcs:

Radius (r) = 7.8/2 = 3.9 m

Area of the shaded region = Area of rectangle + 2*Area of a semicircle - Area of circle with radius 3.5 m

`= lb + 2 * (1)/(2) \pi * {(3.9)}^(2) - \pi * {(3.5)}^(2) \\ \\ = 10.2 * 7.8 + \pi \{{(3.9)}^(2) - (3.5)^(2) \} \\ \\ = 79.56 + \pi {(3.9 + 3.5)} (3.9 - 3.5) \\ \\ = 79.56 + 3.14 * 7.4 * 0.4 \\ \\ = 79.56 + 9.2944 \\ \\ = 88.8544 \\ \\ \approx 88.85 \: {m}^(2)`