Question #ebeed

1 Answer
Apr 2, 2015

To do unit conversions like these ones, all you really need to do is set up a couple of conversion factors.

Conversions factors are used to get from one unit, in your case centimeters, to another unit, feet. The conversion factor for these two units has 1 foot equal to 30.48 cm.

In other words, every 30.48 cm count as 1 foot. As you can see, you've got a little over 30.48 cm in your first conversion, which means you'll have a little over 1 foot

#32cancel("cm") * "1 foot"/(30.48cancel("cm")) = "1.0498 ft"#

The correct number of sig figs for this answer is 2, the number of sig figs given for 32 cm, which means the answer will be

#"32 cm" = color(green)("1.1 ft")#

Now for the second conversion. You must go from milimeters to kilometers using the fact that 1 km equal 1,000,000 mm. You can use this conversion factor to go directly from mm to km, or you can break down the conversion in several steps

SIDE NOTE You can find metric conversion charts here:

#9212cancel("mm") * "1 km"/(10^(6)cancel("mm")) = 9.212 * 10^(-3)"km"#

#9212cancel("mm") * (1cancel("cm"))/(10cancel("mm")) * (1cancel("dm"))/(10cancel("cm")) * (1cancel("m"))/(10cancel("dm")) * (1cancel("dkm"))/(10cancel("m")) * (1cancel("hm"))/(10cancel("dkm")) * "1 km"/(10cancel("hm")) = 9212 * 10^(-6)"km" = 9.212 * 10^(-3)"km"#

The correct number of sig figs in this case is 4, the number of sig figs given for 9212 mm, so the answer will be

#"9212 mm" = color(green)(9.212*10^(-3)"km")#