Question 18
In the diagram, the ratio of the width and the length of the rectangle is 1 : 4. The ratio of the radius of the semicircle to the radius of the biggest circle to the radius of the grey circle to the radius of the two smallest circles is 8 : 4 : 2 : 1. If the area of the rectangle is $1024\ \mathrm{cm}^2$, What is the total area, in $\mathrm{cm}^2$, of the shaded regions? (Use $\pi=3.14$.)
