P = pressure level as measured by the barometer = 0.72 atm = 0.72 x 1.013 x 10⁵ N/m² = 7.3 x 10⁴ N/m² (Since 1 atm = 1.013 x 10⁵ N/m²)
ρ = density of alcohol inside the barometer = 0.79 x 10³ kg/m³
g = acceleration due to gravity = 9.8 m/s²
h = height of level of alcohol in barometer = ?
Pressure level is given as
P = ρ g h
inserting the values
7.3 x 10⁴ N/m² = (0.79 x 10³ kg/m³) (9.8 m/s²) h
h = (7.3 x 10⁴ N/m²) /((0.79 x 10³ kg/m³) (9.8 m/s²))
h = 9.43 m
