You may want to consider adding a note at the top clearly specifying the problem and challenging the reader to come up with an exact solution before proceeding on. It was actually an interesting problem for someone who has not been in high school geometry for 20 years. So simple to specify, yet very much a "whaaaaaaaa" moment there for a moment while I had to reload some stuff in my brain I had not accessed in a long time. A very nice "bite size" math challenge.