A method is given for the analysis of geodesic domes involving plane geometry. The method shows how to calculate all necessary angles and chords, given the length of one side. (MP)

Detailed instructions are given for the construction of the rhombic dodecahedron templates. A discussion of symmetries is included as background information. (MP)

A mathematical derivation is given, developing the cardioid as an epicycloid locus. Curve-stitched designs are given for a family of epicycloids. (MP)

Some practical, hands-on ways in which ideas about geodesic domes can be used in secondary school mathematics are described. Instructions for constructing a one-frequency geodesic sphere are given. (MP)

Worksheets and instructions are given for this activity whose objective is to develop the relationship between the lengths of the sides of a triangle and its classification by angle. (MP)

Construction of colorful braided polyhedra can provide upper elementary students with enjoyable geometric experiences. (SD)

Children's perception and understanding of three-dimensional figures and of operations on them is discussed. Piaget's findings are reviewed and more current research is described. Classroom implications are explored. (SD)

Relationships among the sides are developed for right triangles whose sides are in the ratios 1:3, 1:4, and 1:5. The golden ratio appears in the results which can be used in secondary mathematics. (DC)

Paper-folding activities demonstrate properties of the conic sections and equilateral triangles. (SD)

The author explores relationships among the lengths of sides of a triangle, one of whose angles measures 60 degrees. A computer program designed to search for special triangles is included. (SD)

Three worksheets are provided to help secondary students explore relationships among the areas of a variety of similar figures constructed on the sides of right triangles. The activity is extended to include the relationship among the lengths of the sides of the right triangle. Included are several student worksheets. (DC)

Discusses six examples that discover supplementary geometry theorems by using three elementary theorems about the relationships between angles and intercepted arcs in circles. Topics in the examples include angles formed by parallel lines and the sum of the interior angles of triangles, convex quadrilaterals, star polygons, and hexagons. (MDH)

Problems related to the division of sides of triangles into congruent parts are discussed. (SD)

Students use a series of isosceles right triangles constructed on a geoboard to discover patterns and form generalizations. (MP)

Several activities that can be used to give children more experience with triangles are submitted. By handling triangular shapes and building triangles with strips, pupils can experience a diversity of triangles in a very concrete way. Examination of triangles and nontriangles can help develop understandings of some inequalities. (MP)