two triangles theorem
11Pick's theorem — Given a simple polygon constructed on a grid of equal distanced points (i.e., points with integer coordinates) such that all the polygon s vertices are grid points, Pick s theorem provides a simple formula for calculating the area A of this… …
12Ceva's theorem — For other uses, see Ceva (disambiguation). Ceva s theorem, case 1: the three lines are concurrent at a point O inside ABC …
13Gauss–Bonnet theorem — The Gauss–Bonnet theorem or Gauss–Bonnet formula in differential geometry is an important statement about surfaces which connects their geometry (in the sense of curvature) to their topology (in the sense of the Euler characteristic). It is named …
14Thales' theorem — In geometry, Thales theorem (named after Thales of Miletus) states that if A, B and C are points on a circle where the line AC is a diameter of the circle, then the angle ABC is a right angle. Thales theorem is a special case of the inscribed… …
15Crystallographic restriction theorem — The crystallographic restriction theorem in its basic form was based on the observation that the rotational symmetries of a crystal are usually limited to 2 fold, 3 fold, 4 fold, and 6 fold. However, quasicrystals can occur with other symmetries …
16Brouwer fixed point theorem — In mathematics, the Brouwer fixed point theorem is an important fixed point theorem that applies to finite dimensional spaces and which forms the basis for several general fixed point theorems. It is named after Dutch mathematician L. E. J.… …
17Hurwitz's automorphisms theorem — In mathematics, Hurwitz s automorphisms theorem bounds the group of automorphisms, via orientation preserving conformal mappings, of a compact Riemann surface of genus g > 1, telling us that the order of the group of such automorphisms is bounded …
18Thébault's theorem — is the name given variously to one of the geometry problems proposed by the French mathematician Victor Thébault, individually known as Thébault s problem I, II, and III.Thébault s problem IGiven any parallelogram, construct on its sides four… …
19Pythagorean theorem — Geom. the theorem that the square of the hypotenuse of a right triangle is equal to the sum of the squares of the other two sides. [1905 10] * * * Rule relating the lengths of the sides of a right triangle. It says that the sum of the squares of… …
20Kakutani fixed point theorem — In mathematical analysis, the Kakutani fixed point theorem is a fixed point theorem for set valued functions. It provides sufficient conditions for a set valued function defined on a convex, compact subset of a Euclidean space to have a fixed… …
