When an aircraft takes off, it accelerates until it reaches its takeoff speed $V$. In doing so it uses up a distance $R$ of the runway, where $R$ is proportional to the square of the of the takeoff speed. If $V$ is measured in miles per hour and $R$ is measured in feet, then $0.1638$ is the constant of proportionality. If an aircraft has a takeoff speed of about $210$ miles per hour, how much runway does it need?

feet help (numbers)