One mile = 1,000 feet
...well, paces. Roman. It was a thousand paces, or "mille" paces -- as metric a unit as you could want. Roman pace being about 5 Roman feet, this works out to 1,760 yards, or 5,280 feet. Or 70 laps in a standard US 25 yard swiming pool. All of which I know without having to look it up. NM's one minute of arc at the equator (or along a great circle), 6,080 ft. The minutes and arcs I knew, the feet I had to check on. Incidentally, do you know the derivation of the meter?
Granted, remembering that there are 43,560 square feet (4,840 square yards) to an acre is a bit of knowledge I'm called on to use less frequently.
A furlong, that's easy: 220 yards, or 1/8 mile. And your mile a minute is 161,280 furlongs per fortnight, which is of course, the proper answer to report to the cop who pulls you over next time.
Perch is really a trick question -- the unit may refer to length (5.5 yards), area (a square rod, 1/160th acre, or 272 sqft), or a mass 16.5 feet long, 1 foot high, and 1.5 feet wide. Even I don't routinely use this as a general rule. If we had a perch of water, it would be 7,709 pounds, roughly. Assuming stone at thrice the density of water, the mason's perch is about 23,125 pounds, 1,650 stone, or 11.5 tons.
Or 1/10 of an IWE mille-lard-ass.
That's my answer, me lard.
