Aegyptian (fractions) p/q=1/a+1/b+1/c...

Amicable (numbers) Each one is the sum of divisors of the other

Antiparallel Antiparallel lines

Arithmetic (sequence) U_{n+1}=U_{n}+a

Bernoulli (numbers) 1, -1/2, 1/6, 0, -1/30, 0, 1/42...

Bezier (curves) interpolate with Bezier curves

Bézout (theorem) GCD(a,b)=1 <=>au+bv=1

Bretschneider Heron, Bretschneider and Brahmagupta relations

Brianchon (theorem) Pascal and Brianchon theorems

Butterfly (theorem) Butterfly theorem

Cayley-Menger (determinant) Volume of a tetrahedron, Piero della Francesca formula

Ceva (theorem) Concurrent lines

Congruence Remainders and modulo...

Congruent (numbers) x²±n=y²

Conic sections Ellipses, hyperbolas et parabolas

Descartes (formulae) relation of touching circles radii

Diophantine (equations) ax + by = c

Divisors Number and sum of divisors of n

Equation (2nd degree) ax²+bx+c=0

Equation (3rd degree) ax³+bx²+cx+d=0

Equation (4th degree) ax^{4}+bx³+cx²+dx+e=0

Euclide (algorithm) Calculation of GCD

Euler (cycle) Going through all lines of a graph

Euler (line) Euler line and Euler circle

Euler (relation) Relation between radius od incircle and circumcircle

Euler (formulae) Relation S+F=A+2 in a polyhedron

Fermat (numbers) Prime numbers 2^{n}+1

Feuerbach (theorem) Euler circle touches incircle and excircles

Fibonnaci (numbers) 1,2,3,5,8,13...

Fractals Koch curve, dragons, Mandelbrot set...

Geometric (sequence) Sum of a geometric series

Grinberg (relation) necessary condition for hamiltonian circuit

Hammiltonian (path) Going through all vertices of a graph

Harmonic (conjugate) Relative to 2 lines, a circle or a conic section

Heron Heron, Bretschneider and Brahmagupta relations

Incircle Some property of incircle and excircles

Inversion Circle inversion

La Hire (theorem) Draw ellipses

Lemoine (point) Intersection point of symedians

Mascheroni Constructions with compass alone

Mersenne (numbers) Prime numbers 2^{n}-1

Napoleon (Problem) Some Napoleon problems

Pascal (theorem) Pascal and Brianchon theorems

Pell (equation) x²-Dy²=K

Perfect (Numbers) Number equals the sum of its divisors

Planar (graph) Drawn on a plane without crossing edges

Pole and polar Relative to 2 lines, a circle or a conic section

Powers (sum of) 1+2^{n}+3^{n}+4^{n}...

Projective (geometry) Basic notions in projective geometry

Ptolemy (theorem) xy = ac+bd

Pythagora (theorem) x²+y²=z²

Pythagora (triples) x²+y²=z²

Renaldini Approximate constructions of regular n-gon

Soddy (formulae) relation of touching circles radii

Soddy (point) Circles touching three others, isoperimeter point

Squares (sum of) n=x²+y²+...

Squaring (the circle) Approximate constructions

Triangular (numbers) 1,3,6,11...

Trigonometric (relations) About cos(a+b) etc...

Trigonometric (values) Specific values of sin(x) etc...