Girard Desargues facts for kids

Girard Desargues (born February 21, 1591 – died September 1661) was a smart French mathematician and engineer. He is known as one of the people who started a special kind of math called projective geometry. This type of geometry studies shapes and figures as they appear when projected onto a surface, like how shadows change shape.

Many things are named after him, including Desargues' theorem (a rule in geometry), the Desargues graph (a special kind of network), and even a crater on the Moon called Desargues.

Pratique du trait a preuves (1643) is one of Desargues's works.

Early Life and Family

Girard Desargues was born in Lyon, a city in France. His family was very involved in working for the French king. His father had important jobs, such as being a royal notary (someone who prepares legal documents) and collecting taxes for the city and church.

Desargues as an Engineer and Architect

Before 1645, Desargues worked as a teacher. He might also have been an engineer and advisor to a powerful French leader named Cardinal Richelieu.

From 1645, Desargues became an architect. He designed many buildings in Paris and Lyon, both for private people and for public use. As an engineer, he created a special system to pump water. He installed this system near Paris. It used a new idea at the time, based on a type of wheel called an epicycloidal wheel.

His Work in Geometry

Desargues was very interested in how we see things, especially in perspective. Perspective is the art of drawing objects on a flat surface so that they look like they have depth and distance. His studies on perspective and how shapes are projected were very important. They built on ideas from earlier scientists like Alhazen and Kepler. Desargues combined these old ideas with the art techniques of the Renaissance period.

One of his most famous writings is called "Rough draft for an essay on the results of taking plane sections of a cone" (1639). This work is often mentioned by other mathematicians.

Later Life and Legacy

Later in his life, Desargues published a paper with a mysterious title: DALG. Most people believe this stands for Des Argues, Lyonnais, Géometre, which means "Desargues, from Lyon, Geometer."

His important work was forgotten for a while but was found again and published in 1864. A collection of all his works was put together in 1951. The 1864 collection is still available today.

Girard Desargues passed away in Lyon, the city where he was born.

See also

In Spanish: Girard Desargues para niños