yeah ofcourse what kind of question
By using measuring tools with metric measurements on them.
Any square unit you like can be used to measure the area of a postcard, however to make the numbers have a reasonable size and ease of handling, I would suggest using square centimetres as a postcard is about hand size (and likely to be about 15cm by 10cm).
Yes
In the Metric System, a centimeter is a unit of measure for length.
It derives from the word's meaning: "measure".
Volume is measured in the metric system using liters (L) or milliliters (mL). One liter is equal to 1000 milliliters.
There are many different occasions when a person would want to measure the temperature using the metric system. For example, if a friend from the UK wanted to know the temperature at one's house in Wisconsin, it would be polite to convert the temperature to Celsius so that it makes sense to one's friend.
Meters if you're using the metric system. Otherwise use feet.
Mass is typically measured in the metric system using a scale or balance. The unit of measurement for mass in the metric system is the gram (g) or its multiples such as kilograms (kg) and milligrams (mg).
In all the continents are using some countries are using the metric system more in Asia and Europe most of the countries are using the metric system.
Metres or kilometres in metric; yards or miles in Imperial
The French word "mètre" simply means "measure".