Ajet engine is to be designed for an altitude of 12,000 m, where the atmospheric pressure is 19.3 kpa. the jet nozzle has a supersonic exit mach number and is perfectly expanded. the stag- nation pressure and temperature of the gas are 100 kpa and 600 °c. the flow rate of gas is 45 kg/s. calculate the throat area, exit area, and exit velocity. use k = 1.4 and r = 260 j/kg ∙ k for the gas.