Farhan walks 4 km east from a bus stop, turns left and walks 3 km. What is the shortest distance between Farhan and the bus stop now?

Explanation

1. 01

   Left from east is north, so the legs are 4 km east and 3 km north, at right angles.

2. 02

   Shortest distance $= \sqrt{4^2 + 3^2} = \sqrt{25} = 5$ km.