"From Figure 4 he sees a parallelogram equal to a rectangle of the same base and altitude. Cut out and…

"The student sees the trapezoid is equal in area to a rectangle whose base is the average base of the…

"The student sees the trapezoid is equal in area to a rectangle whose base is the average base of the…

"The triangle ABC is divided into 2 right triangles I and II. ABC is seen to be equal to 1/2 of the…

"The child sees triangle ACB = triangle ADB, and that I + II = CA - DB; and so he sees that the area…

"Fig. 3 shows triangle I = triangle II, III = IV, and so triangle ABC = 1/2 of rectangle ABDE. The fact…

Illustration showing a circle with an inscribed and circumscribed quadrilateral.

Illustration of a circle inside of 2 concentric rectangles whose vertices are connected by line segments.

A regular body with six square faces; a rectangular parallelopiped, having all its edges equal.

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

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…

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

A flashcard featuring an illustration of a Pyramid with a Rectangular Base

Showing different types of forms or shapes: rectangle, right triangle, acute triangle, and obtuse triangle.

This fraction chart can be used for students to find A, B, and C in percentage. It can also be used…

An illustration of a rectangle shaped steel magnet with "consequent poles at a and b." -Century, 1889

An orthographic projection of a pyramid from three dimensional space into two dimensional space

Illustration of parallelogram AEFC drawn two different ways with base b and altitude/height a used to…

Parallelogram with dimensions drawn to show relationship to the area of a rectangle.

Illustration of a decagonal prism with regular decagons for bases and rectangular faces. The hidden…

Illustration of a right decagonal prism with regular decagons for bases and rectangular faces.

Illustration of a right decagonal prism with regular decagons for bases and rectangular faces. The prism…

Illustration of a swimming pool and water hose that is in the shape of a hollow regular decagonal prism…

"The prism of the first order consists of four rectangular vertical faces, each of which intersects…

Illustration of a hollow right heptagonal/septagonal prism with regular heptagons/septagons for bases…

Illustration of a regular right heptagonal/septagonal prism with regular heptagons/septagons for bases…

Illustration of a right heptagonal/septagonal prism with regular heptagons/septagons for bases and rectangular…

Illustration of a right heptagonal/septagonal prism with regular heptagons/septagons for bases and rectangular…

Illustration of a right hexagonal prism with a height less than the length of the edge of the hexagon.

Illustration of a right hexagonal prism with a height greater than the length of the edge of the hexagon.

Illustration of a right hexagonal prism with hexagons for bases and square faces. The hidden edges are…

Illustration of a right hexagonal prism with hexagons for bases and rectangular faces. The height of…

Illustration of a right nonagonal prism with regular nonagons for bases and rectangular faces. The hidden…

Illustration of a right nonagonal prism with regular nonagons for bases and rectangular faces. The height…

Illustration of a right octagonal prism with regular octagons for bases and rectangular faces. The hidden…

Illustration of a right octagonal prism with regular octagons for bases and rectangular faces. The height…

Illustration of a right octagonal prism with octagons for bases and rectangular faces. The height of…

Illustration of a right octagonal prism, with octagons for bases and rectangular faces, that is resting…

Illustration of a right pentagonal prism with regular pentagons for bases and rectangular faces. The…

Illustration of a right pentagonal prism with regular pentagons for bases and rectangular faces. The…

Illustration of a right pentagonal prism with regular pentagons for bases and rectangular faces. The…

Illustration of a non-regular decagonal prism in the shape of a star. Then ends/bases are made of star-shaped…

Illustration of a non-regular decagonal prism in the shape of a star. Then ends/bases are made of star-shaped…

Side view of a non-regular decagonal prism in the shape of a star. Then ends/bases are made of star-shaped…

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

Illustration of 2 Similar right octagonal prisms. The height and length of the edges of the smaller…