We convert from km to cm.
1.2 km = 120 000 cm.
If the map is made on a scale of 1: 20,000, in cm
So we have to divide 120,000 / 20,000 to know how many centimeters that distance on the map is represented.
Finally the answer is 6 centimeters. That is, 1.2 km equals 6 centimeters on the map