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.
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…
Flashcard of a Pyramid with a Rectangular Base
A flashcard featuring an illustration of a Pyramid with a Rectangular Base
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
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 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. 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…
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…