Answer:
[tex]\large \boxed{\text{0.763 atm}}[/tex]
Explanation:
1 atm = 760 mmHg
[tex]\text{Pressure} = \text{580 mmHg} \times \dfrac{\text{1 atm}}{\text{760 mmHg}} = \textbf{0.763 atm}\\\\\text{The atmospheric pressure in Breckenridge is $\large \boxed{\textbf{0.763 atm}}$}[/tex]