TITLE: what's the formula of the inradius of a general simplex?
QUESTION [5 upvotes]: As the title, I just want to know whether there is a general formula for calculating the inradius of a n-simplex. Thank you!

REPLY [3 votes]: Apparently not in complete generality; here is a a formula for a hyperbolic truncated $n$-simplex, and here for a regular simplex. There is also a formula for a triangle.