Worksheets on constructing the circumcenter, the centroid, the orthocenter, the incenter, and the Nine-Point Circle in a triangle are provided for duplication. (DT)

The relationship between area and perimeter is presented through a series of laboratory-type activities and demonstrations. (SD)

Beginning with a construction problem admitting a classical solution, the authors provide other solutions based on algorithmic estimation and transformational geometry. The latter methods are generalized to suggest solutions to other problems; hints to these solutions are provided. Teacher-student discussion could lead in many directions. (SD)

Four geoboard activities for elementary school students are described. (SD)

A classroom activity is described where students divided circular regions into equal sections and reassembled them to determine the formula for the area of a circle. Using an odd number of sections (Instead of an even number) changes the shape of the reassembled pieces but still gives rise to the same formula. (MN)

By changing the Euclidean metric definition, a new geometry is developed. Properties of figures are analyzed and theorems are proven in this new system. (DT)

Many geometric principles can be discovered or illustrated using toothpicks in conjunction with two longer straightedges. (SD)

The author provides a detailed example of the use of the circular geoboard in suggesting an hypothesis which is then proven. (SD)

Eight geometric construction problems with some unusual constraints are presented and then solved using only an unmarked straightedge and a compass. (JT)

Activities are described that involve polyhedrons constructed with a marble inside enabling them to roll across a smooth surface. Directions are given for constructing such a tetrahedron. (DT)

Activities involving the drawing of kites and figures related to kites are described. (SD)