Area of shaded region in rectangle with two circles

Area of rectangle = $20 \times 10 = 200\text{ cm}^2$. Diameter of each circle = $10\text{ cm} \implies r = 5\text{ cm}$. Area of 2 circles = $2 \times \pi r^2 = 2 \times 3.14 \times 25 = 157\text{ cm}^2$. Shaded area = $200 - 157 = 43\text{ cm}^2$.