Is there a thread of photographic technical trivia?

[IpseLux7 6]

We all know, or sort of know what focal length is, right?
So I post this for fun, and in hope that others will post answerable, technical questions for all of us to learn or refresh our knowledge.
Without googling it, or looking this up, does anyone know what focal length lens will fill the short side of a 35mm sensor full, or a film slide (about an inch), with an image of a 6' person standing at 10 feet?
Hint: the mathematical definition of focal length will help....
If you know others, do post them. I joke all the time, I was born ignorant. I don't want to die that way. Ha!
Kind regards everyone.