To convert the speed of the airplane from kilometers per hour to miles per hour, you can use the conversion ratio where 1 kilometer equals about 0.62 miles.
The calculation is as follows:
\[ \text{Speed in miles per hour} = \text{Speed in kilometers per hour} \times 0.62 \]
Substituting the given speed:
\[ \text{Speed in miles per hour} = 900 , \text{km/h} \times 0.62 \] \[ \text{Speed in miles per hour} = 558 , \text{miles per hour} \]
Therefore, the airplane’s speed in miles per hour is 558.