Euclid

The beautiful is always symmetrical.

In geometry, there are no separate roads for kings.

The universe is written in the language of mathematics.

To understand the world, one must first understand its measurements.

The pursuit of knowledge is the noblest of all endeavors.

Through order and reason, we find beauty and truth.

The foundations of knowledge are laid in the simplest of truths.

Magnitudes which coincide with one another are equal to one another.

Any two sides of a triangle are together greater than the remaining side.

In any right-angled triangle the square on the side opposite the right angle equals the sum of the squares on the sides containing the right angle.

If a straight line be cut in extreme and mean ratio, the square on the greater segment added to the half of the whole is five times the square on the half of the whole.

The angles at the base of isosceles triangles are equal to one another; and, if the equal straight lines be produced further, the angles under the base will be equal to one another.

If four magnitudes be proportional, the product of the extremes is equal to the product of the means; and if the product of the extremes be equal to the product of the means, the four magnitudes will be proportional.

There are more prime numbers than any assigned multitude of prime numbers.

To find the greatest common measure of two given numbers not prime to one another.

If two numbers be prime to one another, and a number measure one of them, it will be prime to the remaining number.

To construct a cube from two given straight lines.

Similar solid figures are to one another in the triplicate ratio of their homologous sides.

Any pyramid is a third part of the prism which has the same base with it and equal height.

Spheres are to one another in the triplicate ratio of their respective diameters.