Six equal circles tangent to each other and to the sides of the triangle

Circle Triangle Tangents

Six equal circles tangent to each other and to the sides of the triangle

Illustration showing a circle with equilateral triangles and another circle within.

Circle With Triangles and Circle Within

Illustration showing a circle with equilateral triangles and another circle within.

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

Nonagon Inscribed in a Circle

Illustration of a regular nonagon inscribed in a circle. This could also be described as a circle circumscribed…

A 5-point star made from a non-regular concave decagon in which all sides are equal in length.

Concave Equilateral Decagon

A 5-point star made from a non-regular concave decagon in which all sides are equal in length.

Illustration of 2 regular concentric decagons.

2 Concentric Decagons

Illustration of 2 regular concentric decagons.

Illustration of 2 regular concentric decagons.

2 Concentric Decagons

Illustration of 2 regular concentric decagons.

Illustration of 3 regular concentric decagons that are equally spaced.

3 Concentric Decagons

Illustration of 3 regular concentric decagons that are equally spaced.

Illustration of 4 regular concentric evenly spaced decagons.

4 Concentric Decagons

Illustration of 4 regular concentric evenly spaced decagons.

Illustration of 12 equilateral triangles inscribed in an equilateral dodecagon. Each vertex of the dodecagon contains a vertex of a triangle.

12 Triangles Inscribed In A Dodecagon

Illustration of 12 equilateral triangles inscribed in an equilateral dodecagon. Each vertex of the dodecagon…

Illustration of 3 squares inscribed in an regular dodecagon. Each vertex of the dodecagon is also a vertex of one of the squares.

3 Square Inscribed In A Dodecagon

Illustration of 3 squares inscribed in an regular dodecagon. Each vertex of the dodecagon is also a…

Illustration of a regular hexagon and an equilateral triangle inscribed in a regular dodecagon. This could also be described as an equilateral triangle inscribed in a regular hexagon, which is inscribed in a regular dodecagon.

Hexagon And Triangle Inscribed In A Dodecagon

Illustration of a regular hexagon and an equilateral triangle inscribed in a regular dodecagon. This…

Illustration of a regular hexagon inscribed in a regular dodecagon. This could also be described as a regular dodecagon circumscribed about a regular hexagon.

Hexagon Inscribed In A Dodecagon

Illustration of a regular hexagon inscribed in a regular dodecagon. This could also be described as…

Illustration of a square circumscribed about a regular dodecagon. This could also be described as a dodecagon inscribed in a square.

Square Circumscribed About A Dodecagon

Illustration of a square circumscribed about a regular dodecagon. This could also be described as a…

Illustration of a square inscribed in an regular dodecagon.  This could also be described as a regular dodecagon circumscribed about a square.

Square Inscribed In A Dodecagon

Illustration of a square inscribed in an regular dodecagon. This could also be described as a regular…

Illustration of 2 squares; one inscribed in a regular dodecagon and the other circumscribed about the same dodecagon.

Squares Inscribed and Circumscribed About a Regular Dodecagon

Illustration of 2 squares; one inscribed in a regular dodecagon and the other circumscribed about the…

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

Triangle Inscribed In A Dodecagon

Illustration of an equilateral triangle inscribed in an equilateral dodecagon. This could also be described…

Illustration of 2 regular concentric dodecagons.

2 Concentric Dodecagons

Illustration of 2 regular concentric dodecagons.

Illustration of 2 regular concentric dodecagons.

2 Concentric Dodecagons

Illustration of 2 regular concentric dodecagons.

Illustration of 3 regular concentric dodecagons that are equally spaced.

3 Concentric Dodecagons

Illustration of 3 regular concentric dodecagons that are equally spaced.

Illustration of 4 regular concentric dodecagons that are equally spaced.

4 Concentric Dodecagons

Illustration of 4 regular concentric dodecagons that are equally spaced.

A, B, and C show three types of triangular prisms: right, isosceles, and equilateral. When put together with rectangular prisms, they create the three basic house forms. D is a shed roof and E and F are gable roofs.

Drawing House Forms

A, B, and C show three types of triangular prisms: right, isosceles, and equilateral. When put together…

An equilateral triangle is one having all of its sides equal.

Equilateral

An equilateral triangle is one having all of its sides equal.

"Equilateral pointed arches, described from two centers, the radius being the whole width of the arch." — The Encyclopedia Britannica, 1910

Equilateral Arch

"Equilateral pointed arches, described from two centers, the radius being the whole width of the arch."…

Illustration of an equilateral triangle that shows both the centroid (where the medians of the sides meet) and the incenter (where the angle bisectors meet).

Centers of Equilateral Triangle

Illustration of an equilateral triangle that shows both the centroid (where the medians of the sides…

Illustration of 10 congruent equilateral triangles that have the same center. Each triangle has been rotated 12° in relation to the one next to it. The outer vertices are connected with a smoother curve to form a circle. Hence, the circle is circumscribed about the triangles.

10 Congruent Rotated Equilateral Triangles

Illustration of 10 congruent equilateral triangles that have the same center. Each triangle has been…

Illustration of 10 congruent equilateral triangles that have the same center. Each triangle has been rotated 12° in relation to the one next to it.

10 Congruent Rotated Equilateral Triangles

Illustration of 10 congruent equilateral triangles that have the same center. Each triangle has been…

Illustration of 2 concentric equilateral triangles.

2 Concentric Equilateral Triangles

Illustration of 2 concentric equilateral triangles.

Illustration of 2 concentric equilateral triangles.

2 Concentric Equilateral Triangles

Illustration of 2 concentric equilateral triangles.

Illustration of 20 congruent equilateral triangles that have the same center. Each triangle has been rotated 6° in relation to the one next to it.

20 Congruent Rotated Equilateral Triangles

Illustration of 20 congruent equilateral triangles that have the same center. Each triangle has been…

Illustration of 3 concentric equilateral triangles that are equally spaced.

3 Concentric Equilateral Triangles

Illustration of 3 concentric equilateral triangles that are equally spaced.

Illustration of 4 concentric equilateral triangles that are equally spaced.

4 Concentric Equilateral Triangles

Illustration of 4 concentric equilateral triangles that are equally spaced.

Illustration of 5 congruent equilateral triangles that have the same center. Each triangle has been rotated 24° in relation to the one next to it.

5 Congruent Rotated Equilateral Triangles

Illustration of 5 congruent equilateral triangles that have the same center. Each triangle has been…

A flashcard featuring an illustration of a polygon with three equal sides

Flashcard of a polygon with three equal sides

A flashcard featuring an illustration of a polygon with three equal sides

Regular hexagon with equilateral triangles divided in the interior.

Regular Hexagon

Regular hexagon with equilateral triangles divided in the interior.

Illustration of a regular hexagon with each side divided into thirds by line segments extended to the opposite side.

Regular Hexagon With Segments

Illustration of a regular hexagon with each side divided into thirds by line segments extended to the…

Illustration of 2 regular concentric hexagons.

2 Concentric Hexagons

Illustration of 2 regular concentric hexagons.

Illustration of 2 regular concentric hexagons.

2 Concentric Hexagons

Illustration of 2 regular concentric hexagons.

Illustration of 2 regular concentric hexagons with 6 congruent circles placed between the hexagons so that they are tangent to each other and both the inner and outer hexagons.

2 Concentric Hexagons With Tangent Circles

Illustration of 2 regular concentric hexagons with 6 congruent circles placed between the hexagons so…

Illustration of 3 regular concentric hexagons that are equally spaced.

3 Concentric Hexagons

Illustration of 3 regular concentric hexagons that are equally spaced.

Illustration of 4 regular concentric hexagons that are equally spaced.

4 Concentric Hexagons

Illustration of 4 regular concentric hexagons that are equally spaced.

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

Circle Inscribed in a Nonagon

Illustration of a circle inscribed in a regular nonagon. This could also be described as a regular nonagon…

Illustration of a regular nonagon. A nonagon is a closed geometric figure with 9 sides. A regular nonagon has 9 equal sides and 9 equal angles.

Regular Nonagon

Illustration of a regular nonagon. A nonagon is a closed geometric figure with 9 sides. A regular nonagon…

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

Triangle Inscribed in a Nonagon

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

Illustration of 2 regular concentric nonagons.

2 Concentric Nonagons

Illustration of 2 regular concentric nonagons.

Illustration of 2 regular concentric nonagons.

2 Concentric Nonagons

Illustration of 2 regular concentric nonagons.

Illustration of 3 regular concentric nonagons that are equally spaced.

3 Concentric Nonagons

Illustration of 3 regular concentric nonagons that are equally spaced.

Illustration of 4 regular concentric nonagons that are equally spaced.

4 Concentric Nonagons

Illustration of 4 regular concentric nonagons that are equally spaced.

Illustration of a regular octagon circumscribed about a square. This could also be described as a square inscribed in a regular octagon.

Octagon Circumscribed About a Square

Illustration of a regular octagon circumscribed about a square. This could also be described as a square…

Illustration of 2 regular concentric octagons.

2 Concentric Octagons

Illustration of 2 regular concentric octagons.

Illustration of 2 regular concentric octagons.

2 Concentric Octagons

Illustration of 2 regular concentric octagons.

Illustration of 3 regular concentric octagons that are equally spaced.

3 Concentric Octagons

Illustration of 3 regular concentric octagons that are equally spaced.

Illustration of 4 regular concentric octagons that are equally spaced.

4 Concentric Octagons

Illustration of 4 regular concentric octagons that are equally spaced.

Illustration of 2 concentric pentagons.

2 Concentric Pentagons

Illustration of 2 concentric pentagons.

Illustration of 2 concentric pentagons.

2 Concentric Pentagons

Illustration of 2 concentric pentagons.

Illustration of 2 regular congruent pentagons that have the same center. One pentagon has been rotated 36° in relation to the other.

2 Congruent Rotated Pentagons

Illustration of 2 regular congruent pentagons that have the same center. One pentagon has been rotated…

Illustration of 3 concentric pentagons that are equally spaced.

3 Concentric Pentagons

Illustration of 3 concentric pentagons that are equally spaced.

Illustration of 4 concentric pentagons that are equally spaced.

4 Concentric Pentagons

Illustration of 4 concentric pentagons that are equally spaced.

Illustration of 4 regular congruent pentagons that have the same center. Each pentagon has been rotated 18° in relation to the one next to it.

4 Congruent Rotated Pentagons

Illustration of 4 regular congruent pentagons that have the same center. Each pentagon has been rotated…

Illustration of 8 regular congruent pentagons that have the same center. Each pentagon has been rotated 9° in relation to the one next to it.

8 Congruent Rotated Pentagons

Illustration of 8 regular congruent pentagons that have the same center. Each pentagon has been rotated…

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.