Answer:
The Astronomical Unit (AU) is approximately [tex]92.96\times 10^{6}\,mi[/tex], the ratio of Astronomical Units per mile is [tex]r = 1\,AU\,:\,92.96\times 10^{6}\,mi[/tex].
Explanation:
The distance from the Earth to the Sun is approximately [tex]92.96\times 10^{6}\,mi[/tex], then the Astronomical Unit (AU) is approximately [tex]92.96\times 10^{6}\,mi[/tex]. The ratio can be described by the quantity of miles per Astronomical Unit, then we define:
[tex]r = 1\,AU\,:\,92.96\times 10^{6}\,mi[/tex].