Answer:
Explanation:
There are several that could be used. The goal is to find two that will provide cancellation of units that results in a change from centimeters to kilometers.
[cm = centimeter, m = meters, and km = kilometers]
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There are:
100 cm/m, and
1,000 m/km.
Since these are both conversion factors, we can invert them to obtain:
Y: 1 m/100 cm, and
Z: 1 km/1,000 m
let X: be the 278,420 cm
Since we are going from cm to km, we can see that if we multiply:
Xcm*(Ym/cm)*(Zkm/m)
Xcm*(Ym/cm)*(Zkm/m)
The cm, and m both cancel out, leaving only XYZ km
Therefore:
(278420 cm)*(1m/100cm)*(1km/1,000m) = (278,420 cm)/(100,000cm/km)
(278,420 cm)/(100,000cm/km) = 2.7842 km