Illustration of a two polygons. Polygons may be mutually equiangular without being mutually equilateral.

Equiangular Polygons

Illustration of a two polygons. Polygons may be mutually equiangular without being mutually equilateral.

Illustration of two polygons. Polygons may be mutually equilateral without being mutually equiangular (except for triangles).

Equilateral Polygons

Illustration of two polygons. Polygons may be mutually equilateral without being mutually equiangular…

Illustration of 2 regular concentric heptagons/septagons.

2 Concentric Septagons/Heptagons

Illustration of 2 regular concentric heptagons/septagons.

Illustration of 2 regular concentric heptagons/septagons.

2 Concentric Septagons/Heptagons

Illustration of 2 regular concentric heptagons/septagons.

Illustration of 3 regular concentric heptagons/septagons that are equally spaced.

3 Concentric Septagons/Heptagons

Illustration of 3 regular concentric heptagons/septagons that are equally spaced.

Illustration of 4 regular concentric heptagons/septagons that are equally spaced.

4 Concentric Septagons/Heptagons

Illustration of 4 regular concentric heptagons/septagons that are equally spaced.

Illustration of equal spheres with equilateral and equiangular triangles.

Equal Spheres With Triangles

Illustration of equal spheres with equilateral and equiangular triangles.

Illustration of a square inscribed in a square. The interior square is rotated 45° in relation to the exterior square.

Square Inscribed In A Square

Illustration of a square inscribed in a square. The interior square is rotated 45° in relation to…

Illustration of 12 congruent squares that have the same center. Each square has been rotated 7.5° in relation to the one next to it.

12 Congruent Rotated Squares

Illustration of 12 congruent squares that have the same center. Each square has been rotated 7.5°…

Illustration of 16 congruent squares that have the same center. Each square has been rotated 5.625° in relation to the one next to it.

16 Congruent Rotated Squares

Illustration of 16 congruent squares that have the same center. Each square has been rotated 5.625°…

Illustration of 2 concentric squares whose vertices are connected by line segments.

2 Concentric Squares

Illustration of 2 concentric squares whose vertices are connected by line segments.

Illustration of 2 concentric squares.

2 Concentric Squares

Illustration of 2 concentric squares.

Illustration of 2 concentric squares.

2 Concentric Squares

Illustration of 2 concentric squares.

Illustration of 2 congruent squares that have the same center. One square has been rotated 45° in relation to the other.

2 Congruent Rotated Squares

Illustration of 2 congruent squares that have the same center. One square has been rotated 45° in…

Illustration of 3 concentric squares that are equally spaced.

3 Concentric Squares

Illustration of 3 concentric squares that are equally spaced.

Illustration of 3 congruent squares that have the same center. Each square has been rotated 30° in relation to the one next to it.

3 Congruent Rotated Squares

Illustration of 3 congruent squares that have the same center. Each square has been rotated 30°…

Illustration of 4 concentric squares that are equally spaced.

4 Concentric Squares

Illustration of 4 concentric squares that are equally spaced.

Illustration of 4 congruent squares that have the same center. Each square has been rotated 22.5° in relation to the one next to it.

4 Congruent Rotated Squares

Illustration of 4 congruent squares that have the same center. Each square has been rotated 22.5°…

Illustration of 6 congruent squares that have the same center. Each square has been rotated 15° in relation to the one next to it.

6 Congruent Rotated Squares

Illustration of 6 congruent squares that have the same center. Each square has been rotated 15°…

Illustration of 8 congruent squares that have the same center. Each square has been rotated 11.25° in relation to the one next to it.

8 Congruent Rotated Squares

Illustration of 8 congruent squares that have the same center. Each square has been rotated 11.25°…

Illustration of a square inscribed in a square that is inscribed in another square. Each successive square is rotated 45° in relation to the previous square.

Squares Inscribed In Squares

Illustration of a square inscribed in a square that is inscribed in another square. Each successive…

Illustration of a square inscribed in a square that is inscribed in another square. Each successive square is rotated 45° in relation to the previous square. Diagonals of the largest square are shown.

Squares Inscribed In Squares

Illustration of a square inscribed in a square that is inscribed in another square. Each successive…

Illustration of a square inscribed in a square that is inscribed in another square. Each successive square is rotated 45° in relation to the previous square. Line segments are drawn connecting the vertices of the smallest to the vertices of the largest square.

Squares Inscribed In Squares

Illustration of a square inscribed in a square that is inscribed in another square. Each successive…

"Having equal sides." — Williams, 1889

Equilateral triangle

"Having equal sides." — Williams, 1889

Sketch of equilateral triangle with bisectors, medians, and altitudes.

Equilateral Triangle

Sketch of equilateral triangle with bisectors, medians, and altitudes.

Illustration showing an equilateral triangle (one that has three sides equal).

Equilateral Triangle

Illustration showing an equilateral triangle (one that has three sides equal).

Illustration of a regular nonagon inscribed in an equilateral triangle. This could also be described as an equilateral triangle circumscribed about a regular nonagon.

Nonagon Inscribed in a Triangle

Illustration of a regular nonagon inscribed in an equilateral triangle. This could also be described…

An illustration showing an isosceles triangle in an equilateral triangle.

Equilateral And Isosceles Triangles

An illustration showing an isosceles triangle in an equilateral triangle.

Illustration of an equilateral triangle inscribed in an equilateral triangle. The smaller triangle is created by joining the midpoints of the sides of the larger triangle. The area of the inscribed triangle is 1/4 the area of the larger triangle.

Equilateral Triangle Inscribed In An Equilateral Triangle

Illustration of an equilateral triangle inscribed in an equilateral triangle. The smaller triangle is…

Illustration of an equilateral triangle inscribed in an equilateral triangle by joining the midpoints of the sides of the larger triangle. 3 smaller equilateral triangles are then constructed in the remaining area by joining the midpoints of the other 3 triangles.

Equilateral Triangles Inscribed In An Equilateral Triangle

Illustration of an equilateral triangle inscribed in an equilateral triangle by joining the midpoints…

Illustration of an equilateral triangle inscribed in an equilateral triangle by joining the midpoints of the sides of the larger triangle. Thus, there are 4 equilateral triangles inside of the large triangle. Inside each of the 4 smaller equilateral triangles another equilateral triangle is constructed by joining the midpoints of the sides.

Equilateral Triangles Inscribed In Equilateral Triangles

Illustration of an equilateral triangle inscribed in an equilateral triangle by joining the midpoints…

Illustration of an equilateral triangle inscribed in an equilateral triangle by joining the midpoints of the sides of the larger triangle. Inside the smaller equilateral triangle another inscribed equilateral triangle is constructed by joining the midpoints of the sides.

Equilateral Triangles Inscribed In Equilateral Triangles

Illustration of an equilateral triangle inscribed in an equilateral triangle by joining the midpoints…