 ### Area of Parallelogram

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

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

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

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

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

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

Illustration showing a circle with an inscribed and circumscribed quadrilateral. ### Composite Figure

Illustration of a composite figure made up of rings, rectangles, triangles, etc.. ### Circle Inside Concentric Rectangles

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

A regular body with six square faces; a rectangular parallelopiped, having all its edges equal. ### 3 Square Inscribed In A Dodecagon

Illustration of 3 squares inscribed in an regular dodecagon. Each vertex of the dodecagon is also a… ### Square Circumscribed About A Dodecagon

Illustration of a square circumscribed about a regular dodecagon. This could also be described as a… ### Square Inscribed In A Dodecagon

Illustration of a square inscribed in an regular dodecagon. This could also be described as a regular… ### Squares Inscribed and Circumscribed About a Regular Dodecagon

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

Shading of the right and lower sides gives dimension to drawings. ### Similar Figures

2 rectangles that are similar figures ### Flashcard of a Parallelogram

A flashcard featuring an illustration of a Parallelogram ### Flashcard of a Pyramid with a Rectangular Base

A flashcard featuring an illustration of a Pyramid with a Rectangular Base ### Flashcard of a Rectangle

A flashcard featuring an illustration of a Rectangle ### Flashcard of a Rhombus

A flashcard featuring an illustration of a Rhombus ### Flashcard of a Trapezoid

A flashcard featuring an illustration of a Trapezoid ### Forms

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

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

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

Labeled shapes showing various measures of form. ### Orthographic Pyramid Projection

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

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

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

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

Illustration of a right decagonal prism with regular decagons for bases and rectangular faces. ### Decagonal Prism Resting On Its Side

Illustration of a right decagonal prism with regular decagons for bases and rectangular faces. The prism… ### Swimming Pool Shaped Like A Decagonal Prism

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

"The prism of the first order consists of four rectangular vertical faces, each of which intersects… ### Heptagonal/Septagonal Prism

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

Illustration of a regular right heptagonal/septagonal prism with regular heptagons/septagons for bases… ### Heptagonal/Septagonal Prism

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

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

Illustration of a right hexagonal prism. ### Hexagonal Prism

Illustration of a right hexagonal prism with hidden edges shown. ### Hexagonal Prism

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

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

Illustration of a right hexagonal prism with hexagons for bases and square faces. ### Hexagonal Prism

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

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

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

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

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

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

Illustration of a right octagonal prism with octagons for bases and rectangular faces. The height of… ### Octagonal Prism Resting On Side

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

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

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

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

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

Prism with rectangular bases and cubes drawn in. ### Star-Shaped Decagonal Prism

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

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

Side view of a non-regular decagonal prism in the shape of a star. Then ends/bases are made of star-shaped… ### 2 Octagonal Prisms

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

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