How do I convert #"35.0 yd"# to #"nm"#?

1 Answer
Aug 24, 2016

I got #3.20xx10^10 "nm"#.


You can go about it in more than one way; it depends on which conversion factors you know best. I would recommend that you use the ones you definitely remember.

The general pathway I would approach it is:

#cancel"yd" xx cancel"ft"/cancel"yd" xx cancel"in"/cancel"ft" xx cancel"cm"/cancel"in" xx cancel"m"/cancel"cm" xx "nm"/cancel"m"#

So, the conversion factors we will use are:

  • #"3 ft"# in one #"yd"#
  • #"12 in"# in one #"ft"#
  • #"2.54 cm"# in one #"in"#
  • One #"m"# in #"100 cm"#
  • #10^9 "nm"# in one #"m"#

Therefore, we get:

#35.0 cancel"yd" xx (3 cancel"ft")/cancel"yd" xx (12 cancel"in")/cancel"ft" xx (2.54 cancel"cm")/cancel"in"#
#xx cancel"m"/(100 cancel"cm") xx (10^9"nm")/cancel"m"#

#= color(blue)(3.20xx10^10 "nm")#

You keep three significant figures because all of these conversion factors are exact, and the measurement is known to a specific uncertainty (by default, #pm 0.1#).

So, your answer has #3# significant figures.