The metric system is used to measure the length, mass or capacity of an object. Length is measured in millimetres (mm), centimetres (cm), metres (m) or kilometres (km). Mass or weight is measured in ...

Pupillary distance is the space — measured in millimeters (mm) — from the center of one pupil to another. When you need glasses, an optometrist or an optician will measure this distance to make sure ...

Wondering why the United States measures things in inches and pounds? The answer will definitely surprise you All countries use the metric system to varying degrees. Most of the world has adopted the ...