Online Geometry: Equilateral Triangles, Theorems and Problems - Page 1

Euclid's Elements Book I, 23 Definitions. One-page visual illustration.
Equilateral triangle.

Euclid's Elements Book I, Proposition 3: Given two unequal straight lines, to cut off from the greater a straight line equal to the less.
Equilateral triangle.

Euclid's Elements Book I, Proposition 2: To place at a given point (as an extremity) a straight line equal to a given straight line.
Equilateral triangle.

Euclid's Elements Book I, Proposition 1: On a given finite line to construct an equilateral triangle

Euclid's Elements, Book XIII, Proposition 10 One page visual illustration.

Napoleon's theorems and problems, Index.
Equilateral triangle.

Geometry Problem 404.
External Equilateral triangles, Congruent and Concurrent Lines.

Da Vinci Tetrahedron and Jenn 3D tool for visualizing Coxeter polytopes.
Jenn 3D is a free software license program for visualizing regular polytopes in stereographic projection.

Da Vinci Octahedron and Jenn 3D tool for visualizing Coxeter polytopes.
Jenn 3D is a free software license program for visualizing regular polytopes in stereographic projection.

Da Vinci Icosahedron and Jenn 3D tool for visualizing Coxeter polytopes.
Jenn 3D is a free software license program for visualizing regular polytopes in stereographic projection.

Optical Prism with Equilateral Triangle Form.
Scene created using Prism HD for iPad.

Geometry Problem 876
Equilateral Triangle, any Point, Perpendicular, Right Triangle Area, Sum of Areas.

Geometry Problem 869
Triangle, Median, Three Equilateral Triangles, Collinear Points, Midpoint.

Geometry Problem 832
Quadrilateral, Isosceles triangle, 70-70-40 degrees, Congruence, Auxiliary lines, Equilateral triangle.

Geometry Problem 814.
Two Equilateral Triangles with a common Vertex, Angle.

Geometry Problem 801
Equilateral Triangles, Cevian, Midpoint, Distance, Measurement, Metric Relations.

Geometry Problem 791
Regular Hexagon, Midpoints of Side and Diagonal, Equilateral Triangle, Area.

Geometry Problem 785
Equilateral Triangle, Parallel, Perpendicular.

Geometry Problem 768
Parallelogram with Equilateral Triangles on Sides.

Geometry Problem 767
Equilateral Triangle, Circle tangent to a side, Tangent line, Measurement, Secant.

Geometry Problem 761
Scalene Triangle with an angle of 60 degrees, Euler Line, Equilateral Triangle.

Geometry Problem 759
Equilateral Triangle, Transversal, Trisection of sides, Congruence, Angle.

Geometry Problem 758
Equilateral Triangle, Cevians, Trisection of sides, Congruence, Perpendicular, 90 Degrees.

Geometry Problem 757
Equilateral Triangle, Circumcircle, Chords, a Half of Harmonic Mean.

Geometry Problem 755.
Equilateral Triangle, Circumcircle, Chord, Arc, Midpoints, Perpendicular.

Geometry Problem 754.
Equilateral Triangle, Center, Angle, 60 Degrees, Perimeter.

Geometry Problem 725.
Kurschak's Dodecagon, Square, Equilateral Triangle, Midpoints, 30, 60 Degrees.

Geometry Problem 700.
Equilateral Triangle, Circle, Circular Segment, Midpoint of a side, Metric Relations.