An aeroplane leaves an airport and flies due north at a speed of $1000$ km/hr.At the same time,another aeroplane leaves the same airport and flies due west at a speed of $1200$ km/hr.How far apart will be the two planes after $1\large\frac{1}{2}$ hours?

Question

$\begin{array}{1 1}2000\;km(approx)\\2500\;km(approx)\\2343\;km(approx)\\2433\;km(approx)\end{array} $