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.