 ### Circle to Circle Tangents

Equal circles inside and tangent to the outside circle, also tangent to each other ### 2 Similar Right Circular Cones

Illustration of 2 right circular cones that are similar. ### Coordinate Axis With Perpendiculars Drawn To Form Similar Right Triangles From Positive and Negative Theta, Θ

Angle XOP=Θ and angle XOQ=- Θ. From a point in the terminal side of each a perpendicular line is drawn… ### Coordinate Axis With Perpendiculars Drawn To Form Similar Right Triangles

Angle XOP=Θ and angle XOQ=90+Θ. From a point in the terminal side of each a perpendicular line is… ### 2 Narrow Cylinders on Their Sides

Illustration of 2 narrow right circular cylinders with equal heights (thickness) and different diameters.… ### 2 Right Circular Cylinders

Illustration of 2 right circular cylinders in which one cylinder is twice the height of the other. ### 2 Right Circular Cylinders

Illustration of 2 right circular cylinders in which one cylinder is twice the height and twice the diameter… ### 2 Similar Cylinders

Illustration of 2 similar cylinders. The height and diameter of the smaller cylinder is half that of… ### 2 Soup Can Cylinders

Illustration of 2 soup cans that are similar cylinders. The diameter and height of the smaller can is… ### 3 Similar Cylinders

Illustration of 3 similar cylinders. The height and diameter in each successively smaller cylinder is… ### 3 Similar Cylinders

Illustration of 3 similar cylinders. The height and diameter in each successively smaller cylinder is… ### 2 Concentric Decagons

Illustration of 2 regular concentric decagons. ### 2 Concentric Decagons

Illustration of 2 regular concentric decagons. ### 3 Concentric Decagons

Illustration of 3 regular concentric decagons that are equally spaced. ### 4 Concentric Decagons

Illustration of 4 regular concentric evenly spaced decagons. ### Hexagon Used to Construct Equivalent Triangle

Illustration of a how to construct a triangle equivalent to a given hexagon/polygon. ### Parallelogram Used to Construct Equivalent Square

Illustration of a how to construct a square equivalent to a given parallelogram. ### Pentagon Constructed to be Similar to Given Pentagons

Illustration of a how to construct a pentagon similar to two given pentagons. ### Pyramid Cut By Plane

Diagram used to prove the theorem: "If a pyramid is cut by a plane parallel to the base, the edges are… ### Similar Polyhedrons

Two similar polyhedrons may be decomposed into the same number of tetrahedrons similar, each to each,… ### Two Similar Polyhedrons

Diagram used to prove the theorem: "Two similar polyhedrons may be decomposed into the same number of… ### 2 Octagonal Prisms

Illustration of 2 right octagonal prisms with congruent bases, but different heights. The height of… ### 2 Rectangular Prisms

Illustration of 2 right rectangular prisms. The bases are congruent, but the height of the smaller prism… ### 2 Rectangular Prisms

Illustration of 2 right rectangular prisms. The bases are congruent, but the height of the smaller prism… ### 2 Similar Octagonal Prisms

Illustration of 2 Similar right octagonal prisms. The height and length of the edges of the smaller… ### 4 Congruent Rectangular Prisms

Illustration of 4 congruent rectangular prisms placed in the shape of a square. They are arranged to… ### 4 Hexagonal Prisms

A cluster of 4 right hexagonal prisms with congruent bases, but varying heights. ### 2 Right Pentagonal Pyramids

Illustration of 2 right pentagonal pyramids with hidden edges shown. The pentagonal bases are congruent,… ### 2 Right Rectangular Pyramids

Illustration of 2 right rectangular pyramids with hidden edges shown. The rectangular bases are congruent,… ### Similar Tetrahedrons

The volumes of two similar tetrahedrons are to each other as the cubes of their homologous (corresponding)… ### Two Proportional Tetrahedrons

Diagram used to prove the theorem: "Two tetrahedrons having a trihedral angle in each equal, are to…