Question

1. convert 12,345 mm into km.

Explanation:

Step1: Recall conversion factors

We know that $1\ km = 1000\ m$ and $1\ m=1000\ mm$, so $1\ km = 1000\times1000\ mm= 10^{6}\ mm$.

Step2: Set up the conversion

To convert $12345\ mm$ to $km$, we divide the number of millimeters by the number of millimeters in a kilometer. Let $x$ be the length in kilometers. Then $x=\frac{12345}{10^{6}}$.

Step3: Calculate the result

$\frac{12345}{10^{6}}=0.012345\ km$.

Answer:

$0.012345\ km$