Question 22
The surface of a cube is divided into black and white parts as shown in the diagram below. It is known that the side length of this cube is 4 cm, and on each face, the radius of the smallest quarter circle is 1 cm, the radius of second smallest quarter circle is 2 cm, the radius of second largest quarter circle is 3 cm and the radius of largest quarter circle is 4 cm. What is the sum of the areas, in square centimetres, of all black regions? (The area occupied by the circular curve is negligible. Take $\pi=3$.)
