Here is one of those popular "math" verses, but I've wondered what is the deal with it. Obviously the circumference would have been 1.4159265359 cubits longer, if the diameter were actually 10 cubits.
Maybe it's only in that we are suppose to notice the difference and rounding, or maybe that someone wasn't measuring properly, or that it took the 30 cubit line, and then some... not set it up as a pi "proof text", haha.
Or maybe it's a new paradigm that transcends normal rules. :)
OR...the circumference could have been measured INSIDE a wide rim, and thus be shorter.