> I used a placeholder n, not being sure what exactly this might be
while the accepted answer doesn't explain what the one asking was concern about, which is that this is the length of the side of a regular pentagon in a circle of radius $R$, there is no typo
@BillDubuque Before I request action or report a problem in CURED, I have acted. Please do not post here, if you have not acted accordingly, e.g, Whatever you consider to be "not an answer", before posting here, please downvote such a post.
@amWhy I didn't downvote (yet) because I'm not sure how to best handle an accepted non-answer. Please strive to be more open minded. Not everyone manages the site the same way you do. It is absurd (and rude) to request others not to post here unless they follow your methods.
@BillDubuque Will you please strive to be more open minded. It is telling you did not note the stipulations I wrote. I expect more from users over 100K. Not everyone sees the world from your viewpoint. Please strive to not begrudge the very folks who support CUREDs goals, and those who generally heed your recommendations.
Update: author has edited the answer to clarify how it answers the question. One of the reason's I didn't immediately downvote is that the author was active a half hour earlier so I wanted to give them a chance to clarify before downvoting.
@Jakobian Thanks for helping the author realize what was needed for clarification of said answer. One reason I posted about it here (w/o any request for downvote/deletion etc) was to get the help of others (I had no time), and that worked quite well here, with a nice constructive resolution.