Gradian

Imagine you are turning in a circle. We use angles to measure how much we turn. One way to do this is with a unit called the gradian. People also call it the gon or the grade.

A gradian is part of a system based on the number ten. This is called the centesimal system. It uses groups of one hundred to measure turns. In this system, a right angle is exactly 100 gradians. This is different from the 90 degrees we often use. A full circle is 400 gradians. This makes some math very simple. You can easily see the four parts of a circle. Each part is exactly 100 gradians long.

Using this system makes certain calculations very fast. It helps people find directions by using simple math. For example, if you face 117 gon, you can find other paths. To find the direction to your left, you just look at 17 gon. To find the direction to your right, you look at 217 gon. To find what is behind you, you look at 317 gon. This makes it easy to work with perpendicular angles. Perpendicular means two lines that meet like a perfect corner. However, some math can be harder with this unit. Common angles like 30 or 60 degrees must be written as fractions.

This unit has a long history in France. It started during the French Revolution. It was made to work with the new metric system. People sometimes call it a metric degree. Later, the name gon was used to avoid confusion. In some northern countries, the word grade meant something else. This caused people to pick a new name. In France, it was also known as the centesimal arc.

In German, it was called the new degree. Other languages like Danish and Swedish used similar names. It was an attempt to make all measurements the same.

Today, the gradian is used for special jobs. Surveyors use it to map out the land. People in mining and geology use it too. It is a legally recognized unit in Switzerland. It is also recognized in the European Union.

However, it is not part of the International System of Units. Scientists usually prefer degrees or radians. In the 1990s, many scientific calculators had a gon button. This helped students use trigonometry functions easily. Some newer calculators from the 2010s do not have it. The unit is still a special tool for certain experts.

There is also a link between angles and distance. An early definition of the metre involved the Earth. It was based on the distance from the North Pole to the equator. Because of this, 1 gon is about 100 kilometres along the Earth. A centigon is about 1 kilometre. Even smaller parts like microgons relate to the metre.

This shows how math connects shapes to the real world. Whether we use degrees or gradians, we are measuring our world. Every unit helps us understand how we move through space. It is a way to turn a turn into a number.