>>11598424The meme comes from the fact that for lot of purposes rounding it down to 3 will still work just fine in giving a reasonably correct answer to which ever question it happened to be. As in taking the easy to calculate in your head or practical way of looking at the number or the engineering way.
A practical example could be that your boss asks you for something like "how much material do we need for these new niknaks marketin is proposing" then you answer by taking their diameter which is say 2 inches and say "about 12 square inches of plastic base" when the true answer is 12.4 or 12.56 or 12.564 or... or... depending on the precision truly needed which is something you would calculate with the required precision for the actual schematics or machining instructions. 3 will produce an adequate solution in the right ballpark while being relatively easy to calculate in your head for a quick answer. Similarly you might round the radius from 1.97 to 2 for convenience in that answer.
Obviously no engineer uses 3 in actual work, it's not like it takes a computer longer to calculate with a more accurate number.
