Don't forget significant figures like your science teacher taught you. 841 mm has only 3, and both answers are correct to 3 sig. figs. So it's correct. Another

Don't forget significant figures like your science teacher taught you. 841 mm has only 3, and both answers are correct to 3 sig. figs. So it's correct. Another way to see it. What dimensions should it have for you to deem it correct?