As RTN11 (and I in an earlier post) have said, this question is concerned solely with geometry. Had it include IAS, this would have introduced the added complication of the relationship between the IAS/TAS ratio and the air density. This in turn would have required the inclusion of specific altitudes, and/or atmospheric conditions to enable the actual IAS/TAS ratios to be calculated. The overall result would have been the conversion of a relatively simple question into a much more complicated one. As a number of the posts in this thread indicate, the simple geometric question was too complex for some reader.
Virtually all fields of study have employed the practice of posing questions and seeking to deduce the answers to these questions. The questions are often quite abstract and in most cases include various simplifying assumptions. The question posed by the OP in this thread is simply one example of such a question.
The fact that a question is purely theoretical does not make it unworthy of inclusion in pprune. Consideration of this type of question is often the most effective route to developing a thorough understanding of matters. pprune would be a much poorer site if we were to exclude theoretical questions.
For those who dislike purely theoretical questions I would suggest you adopt what I call the Pilchard Principle. I hate tinned pilchards. The very though of them makes me feel quite unwell to the point that I want to heave. I'm actually feeling a bit queasy just writing about them. But this poses no real problem for me. I simply avoid having anything to do with tinned pilchards. The same method would be just as effective when dealing with purely theoretical questions. If you don't like them don't read them.