Let the distance represented on the map be x cm.
The given information in the form of a table is as follows.
|Distance covered on road in (in km)||18||72|
|Distance represented on map (in cm)||1||x|
The distances covered on road and represented on map are directly proportional to each other. Therefore, we obtain
18/1 = 72/x
x = 72/18 = 4
Hence, the distance represented on the map is 4 cm.