“What does ‘perfectly accurate’ mean?”
“Is there a word or phrase in English that means accurate to an infinite level of precision?” “If a length is ‘perfectly accurate’, it is recorded down to its final decimal place. For example, the measurement of a length that is ‘perfectly accurate’ may correspond with an exact length’s size.”
“In a mathematical context, the word was exact.” “An exact calculation always gives the mathematically expected result.” “If you approximate, you get a result that looks similar, but also a bit closer.” “A circle of radius 1 is exactly 2, which is approximately 6.283. The circumference of this circle is 2, which is approximately 790.” “For instance, financial math calculations are usually done with exact arithmetic (using integers or fixed-point decimal numbers, with well-defined rounding rules), whereas physical math is usually done with inexact or approximate arithmetic (using floating point numbers, with rounding rules intended to maximize the precision of the result but not always to be perfectly reproducible).” “Strictly speaking, a physical measurement cannot be exact (the height of a stick has no end decimal place).” “Notwithstanding the use of the word exactly, the precision of measurement is so great that the uncertainty about the measured quantity can never be ignored. As such, you can still use the term exact to mean that the precision of measurement is so great that the uncertainty about the measured quantity will never matter.” “You can also use perfectly accurate in this context (again, meaning so accurate that any inaccuracy is irrelevant).”
