Abstract: A combination of devices that demonstrate visually and on an intuitive level mathematical principles relating to the circle including the number &pgr;, the relationship between circumference, diameter, radius and &pgr;, and the relationship between the area of a circle formed of circle sectors and an approximate parallelogram obtained by rearranging the circle sectors.

Abstract: The present invention provides a variety of laminated plastic activity boards that allow the individual to visualize and have interactive exploration of conic sections and their definitions. This allows for more class time to be spent investigating the concept of conic sections opposed to teachers lecturing and the students having to memorize them. The user is able to notice patterns which develop while drawing specific sets of conic sections by forming conjectures based on the observed outcomes of the activities. Each activity board has a reusable laminated surface which allows the ink used from a marker to be visible but not permanent. The surface can be wiped clean with a moist paper towel once the activity is completed. There are a total of four activity boards which operate independently of each other and contain different concepts. The four boards teach principles relating to the circle, ellipse, parabola and hyperbola.

Abstract: A method and apparatus for teaching a relationship of trigonometric functions between a unit circle and a rectangular coordinate system has a primary flexible member movable between a circular configuration defining the unit circle, and a straight configuration defining the rectangular coordinate system. A plurality of secondary linear members are removably coupled at attachment points along the flexible member. The linear members are movable with the flexible member between a unit circle position and a rectangular coordinate position. In the unit circle position, each linear member is oriented with respect to the unit circle to demonstrate and represent a trigonometric function. In the rectangular coordinate position, each linear member extends perpendicularly from the flexible member defining trigonometric wave forms. The flexible member and linear members physically represent the trigonometric functions and moving the members between the two systems demonstrates the relationship between them.

Abstract: A toy that may be used to make three-dimensional designs from elastic members comprises a base and at least one, and preferably two, vertical sidewalls rotatable relative to the base. The base and the at least one sidewall each have a face surface with a plurality of retaining means disposed thereon. A plurality of elastic members may be secured to the plurality of retaining means and thereby suspended between the base and the at least one sidewall to form a three-dimensional design, for example, each member may be attached at a first point along the member to a retaining means on the at least one sidewall and at a second point along the member to a retaining means on the base. The at least one sidewall or the base can be rotated to vary the length of the elastic members, thereby changing the three-dimensional design formed thereby.

Abstract: A geometric figure teaching aid includes a base, a rod affixed to and extending from the base, and a series of side members interconnected with the base and the rod. The base is preferably formed of a translucent material, and the rod is mounted to the base at a first end and terminates at a second end spaced above the base. The side members extend from edges defined by the base member and are engaged with the rod at the second end of the rod. Clips are mounted to the side members, and are adapted to receive labels for identifying characteristics of the geometric figure represented by the side member, or to carry a given value corresponding to a problem. Lines are provided on the base, extending from the center of the base, from which the rod extends, outwardly to locations at which the side members are engaged with the base. The lines correspond to dimensions or aspects of the geometric figure.

Abstract: A geoboard has a board member with a plurality, advantageously four edges. An array of holes which is preferably in the form of a matrix, is provided in the board member for receiving slidably mounted push-up pins. Each push-up pin has upper and lower positions and the pins are arranged in the matrix for engagement by an elastic band to form shapes on the board member. Each of the edges includes spaced-apart notches for receiving fixed slider pins which extend in a row on a slider. Each slider is slidably mounted along one of the edges for extending the matrix of push-up pins.

Abstract: A geometry board having pegs arranged on its top face for the demonstration of planar geometric figures by stretching of elastic bands about the pegs. The disclosed board is of clear injection-molded plastic and has a square face with the pegs arranged in a grid on the face including along edges of the board. Pegs along the edges are in the shape of semi-cylinders and the arrangement is such that a pair of boards may be located side-by-side so that the semi-cylinders are paired up so that each pair of semi-cylinders forms a single cylinder. Pegs located at the corners of the board are in the shape of quarter-cylinders so that when four corner pegs are located at the center of four boards laid side-by-side the four quarter-cylinders form a singe cylinder. When four boards are assembled together a Cartesian coordinate system is obtain with x- and y-axes along adjacent edges of the boards and point (0,0) located at the intersection of all four boards.

Abstract: An educational board for use in demonstrating mathematical principles has a surface marked with a circle having its circumference marked with gradations indicating 360 degrees. The board is provided with pins to mark any angular displacement along the circumference and connecting elastic bands which are stretched around the pins to create shapes inscribed in the circle.

Abstract: A tension model device is disclosed which has: Three struts which cross each other at or near the center portion of each strut; and a plurality of corresponding tension strands. The strands are joined from each end of all the struts to each end of the other struts. To facilitate assembly, a removable block is inserted where the struts cross each other. The block has three notches on its surface that engage the struts and space them from each other.