A possible logical flaw based on similar triangles is discussed with the Sherlock Holmes mystery, "The Muskgrave Ritual." The possible flaw has to do with the need for two trees to have equal growth rates over a 250-year period in order for the solution presented to work. (MP)

Geoboards are viewed as excellent vehicles for developing intuitive understandings of various topics in transformational geometry. The activities described are designed to show pupils that when a triangle or parallelogram is subjected to a transformation called a shear, its area is not changed. Ways for finding areas are detailed. (MP)

A complete characterization of minimum conditions for congruence of quadrilaterals is presented. Convex quadrilaterals are treated first, then concave quadrilaterals are considered. A study of such minimum conditions is seen to provide some interesting and important activities for students. Only background in triangle congruence is necessary. (MP)

Ways of working with mirrors to explore the reflections of various objects are noted. Angles and formulas helpful in constructing interesting "reflection chambers" are provided. (MP)

Presented is an edited transcript of an interview with Dr. Caleb Gattegno exploring the teaching approaches used in a film of the same name. (MP)

Worksheets for duplication concerned with classification and measure of various geometric shapes are given. (MK)

This module, designed for use at the high school level as a four- to eight-hour topic, includes: the geometry of a sphere, the coordinate system used to describe points on the earth's surface, parallel and meridian sailing, and the solution of right spherical triangles. (Author/MK)

Although traditional instructional methods and textbooks mitigate against it, investigation can be a viable alternative strategy in the geometry classroom. Many theorems in geometry, such as Euclidean space, lend themselves easily to student experimentation. (Author/SJL)

This study attempts to explain certain difficulties which ninth grade students face in tackling geometrical "problems to prove," by relating them to general and to specific rigidity and cognitive style variables. The results confirm the conceptual analysis of Geometric Rigidity (GR). (MP)

Seven major reasons to consider geometry as a basic skill are presented. (MP)

In this "thank-you" letter to Mr. Pascal, many applications for Pascal's triangle are pointed out. (MK)

Suggests that sex differences in spatial visualization and restructurization are confounded by differences in attitudes toward mathematics and mathematical abilities as well as by task and ego-oriented factors. Subjects were 86 male and female college students. (Author/MP)

Algebra is used to expand the historic construction of the arithmetic, geometric, and harmonic means to include the quadratic mean and a fifth mean. (MK)

Presented are suggestions for teaching metric conversion and the properties of quadrilaterals. (MK)

This study attempted to determine if teachers discriminate against female learners of mathematics. More than 1000 secondary mathematics teachers were asked to grade four geometry proofs. Student sex and ability were the independent variables. Analysis yielded no significant F ratios for either of the main effects or their interaction. (Author/MK)