- Brookstone Geo 2 and 6
- geometry
- the famous "1/7" triangle
- ptolemy's theorems
- pythagorean and galileo's law
- pythagorean theorem (proof)
- ratio of areas-1
- ratio of areas-2
- regular polygons-1
- sum of the interior angles of a n-gon
- secant-secant theorem
- square vs rhombus
- supplementary angles
- tangent-chord angle
- the famous "1/5" square
- Thales' theorem
- tangent-secant theorem
- the angle bisector theorems
- the lunes of Alhazen
- the lune of Hippocrates
- the outer Napoleon triangle
- triangle angle-sum theorem
- the three squares problem
- triangle midpoint theorem
- vivianni's theorem
- proof of pythagorean-5
- parallel chords theorem
- five squares
- Garfield's proof for pythagorean theorem
- median to the hypotenuse
- power of a point
- chord theorem
- cuboid
- diagonals of n-gons
- double reflection
- equal chords
- equilateral triangle (SAS)
- equal chords-1
- area of a triangle
- areas inside a trapezoid
- areas of similar triangles
- area of an equilateral triangle
- area of a triangle-2
- areas inside a parallelogram
- areas-3
- area of a trapezoid
- area of a quadrilateral
- area of a kite
- area of a rectangle
- archimedes' "salinon"
- area of a parallelogram
- area of a rectangle-1
- archimedes' arbelos
- a Reuleaux triangle
- a square in a square
- angle bisector as locus
- angle between secants
- Johnson's theorem
- geometric mean theorem
- frustum of a right cone
- proof of pythagorean-9
- euclid's proof of pythagorean
- circles of a regular n-gon