Question

practice creating a conversion
units of length
customary system units & metric system units
1 inch & 2.54 centimeters
1 foot & 0.3048 meters
1 mile & 1.61 kilometers
which conversion factor would you use to convert kilometers to miles?
options:
$\frac{1 \text{mile}}{1.61 \text{km}}$
$\frac{1.61 \text{km}}{1 \text{mile}}$
$\frac{1.61 \text{miles}}{1 \text{km}}$
$\frac{1 \text{km}}{1.61 \text{miles}}$

Explanation:

Step1: Identify given conversion

From the table: $1 \text{ mile} = 1.61 \text{ kilometers}$

Step2: Rearrange for km to miles

We need a factor where km cancels. Rearrange to get $\frac{1 \text{ mile}}{1.61 \text{ km}}$. When multiplying by kilometers, the km units cancel, leaving miles.

Answer:

$\boldsymbol{\frac{1 \text{ mile}}{1.61 \text{ km}}}$ (the second option)