$1.$ The Boeing $777$ is powered by the GE$90$ turbofan engine. The engine has a diameter $\backslash (=3\mathrm{.}1\backslash )$ m and length $\backslash (=7\mathrm{.}3\backslash$mathrm$\{$~m$\}\backslash ).$ Consider steady flight at $\backslash (280\backslash$mathrm$\{$~m$\}/\backslash$mathrm$\{$s$\}\backslash )$ at an altitude where the temperature is $240$ K and the pressure is $45$ kPa $.$ Estimate the total mass flow rate of air entering the engine.

$(5$ points$)$