Answer:
This is just my thinking
Explanation:
The conditions you mentioned are obviously not enough to use the data to calculate the solution. The attached picture can clearly explain the reason. The vertical line segment on the diameter of the large circle can have countless changes due to the size changing of the circle. Try to find out if something is missing.
The left fig: shaded area is 0.98, while the right side fig is 1.04
May be i do not get the right logic, because the two small semicircle also expand or shrink with the change of large one.