KJW said:

dv said:

18

Actually, this is not correct. In fact, there is insufficient information to obtain a correct numerical answer. My answer was based on the assumption that there is sufficient information to answer the question, and under this assumption, the only possible answer is 18. That’s because the assumption implies that the area is constant with respect to the angle the 6 unit line makes to the diameter. I actually tested that by looking at two particular angles, and for those two angles, the area is indeed 18. But when I examined the area for arbitrary angle, it is not constant. But because the angles I chose were special, they just happen to both lead to an area of 18.