M is the abbreviation of Meter and dm is an abbreviation of Decimeter. A meter is a unit of length as prescribed by the international system of units. This unit is used to measure the length. Decimeter is the smaller unit of meter. 10 Decimeter makes one meter, which means 1M equals 10DM. So where there are 73 meters, there would be 73 * 10 Decimeters in it. This is shown as below.
