How do you measure something to see if its 55mm?

1. How do you measure mm on a ruler?
2. How many mm means 1 inch?

How do you measure mm on a ruler?

Locate the zero end of the ruler, and then count each individual mark along the edge of the ruler. Each mark represents 1 millimeter or mm, so counting five marks is the same as counting 5 millimeters, counting 10 marks is the same as counting 10 millimeters and so on.

How many mm means 1 inch?

One inch is equal to 25.4 millimeters.