This slides deal with a topographic map with a ratio scale of 1:50 000. They focus the metric table and how to convert mm and cm into km for a real ground distance.

1. MAPINFO Topographic map

2. TOPOGRAPHIC MAP
The meaning of the representative fraction scale of the Topographic
map.
The scale of 1:50 000 in reality means: 1 nominator (mm)
50 000 denominator (mm)
Note that the measurement units of both the nominator (representing
the map distance) and denominator (representing the ground
distance or distance in reality) ARE ALWAYS THE SAME.

3. RATION OF 1:50 000
Scale is a pure ratio between the size of the map and the real area in reality or the area on the ground. This notion should be
very clearly understood. (The real area represented by the map is 50 000 times bigger than the Topographic map: Scale 1:50
000
Watch a YouTube video that will explain how to use the scale of 1:50 000 to determine the ground distance in km (distance in
reality)
Map distance measured on the 1:50 000 Topographic map: 25 cm
Scale of the Topographic map: 1:50 000
The Scale means: 1 mm on the map represents 50 000 mm in reality
Therefore 25 mm on the map represents 25mm x 50 000 mm in reality =1 250 000 mm
in reality
To convert this 1 250 000 mm in reality on km, one must divide the number of mm with 1 000 000
Therefore 25 mm on the map represents 25mm x 50 000 (because 1 000 000 mm = 1 km) 1 000 000
= 1 250 000 mm
1 000 000
= 1, 25 km