Euclid

Euclid ( c. 325 - 265 BC) of Alexandria was a Greek mathematician and geometrician, known for his book "The Elements", a treaties on mathematics. He is considered the "father of geometry", and also by many the leading mathematics teacher of all time. He founded a school of Mathematics in Alexandria, and flourished about 300 B.C.

Wisdom & Quotes

• There is no royal road to geometry.

-quoted in Proclus' Commentaries

• What has been affirmed without proof can also be denied without proof.
• An 'unit' is that by virtue of which each of the things that exist is called one.

A 'number' is a multiple composed of units.

His five postulates are:

• To draw a straight line from any point to any point
• To produce a finite straight line continuously in a straight line
• To describe a circle with any centre and distance
• That all right angles are equal to one another
• That, if a straight line falling on two straight lines make the interior angles on the same side less than two right angles, the two straight lines, if produced indefinitely, meet on that side on which are the angles less than the two right angles.

His five Common notions are:

• Things which are equal to the same thing are also equal to one another.
• If equals be added to equals, the wholes are equal.
• If equals be subtracted from equals, the remainders are equal.
• Things which coincide with one another are equal to one another.
• The whole is greater than the part.

Chanakya

Nearby pages
Euclid of Megara, Eudaemonism, Eudocia, Eudora Welty, Eudoxus of Cnidus