The process of investigating some of the properties of diagonals and other geometric concepts with a group of 11-year-old girls is presented. Possible changes that could have been made in the lesson are discussed, and examples of individual student work are provided. (MP)

Details of the investigation of a device that produces unusual transformations in the plane are provided, along with the directions several students took in their studies. (MP)

A new approach to classifying quadrilaterals is presented that tries to classify all possible combinations of shapes and angles by removing the traditional Euclidean viewpoints. The document concludes with a brief look at other types of polygons. (MP)

There were 120 pupils in years 1 to 5 from two schools which were interviewed using specially prepared tasks to study the variety of interpretations given to letters by adolescents. Results indicate that two distinct conceptual understandings of the role played by a letter in relation to geometrical data exist in pupil's thinking. (Author/TG)

A resource applications geometry module was developed and tested. Attitude data were collected. (MK)

A short account is given of the Coxeter Symposium on geometry. Included are brief descriptions of selected sessions and a description of a touchable geometry display. (MK)

A group of unsolved geometry problems is presented. Several problems that were unsolved for a length of time and then solved are also discussed. (MK)

The conditions necessary for a circumscribable quadrilateral also to be inscribable are discussed. Three propositions are presented and proved. (MK)

Demonstrates the instructional value of supplementary media presentations using first year engineering students randomly split into 11 descriptive geometry classes; five received multimedia instruction, and six did not. Data compared each study group in relation to competency in the subject, achievement, visualization of spatial relationships, and…

Topics discussed include: reasons for strategies; the use of a hierarchy of spaces from topological to Euclidean in teaching; structural strategies; pedagogical strategies; and mathematical strategies. (MP)

Topics discussed include: maximizing the volume of a box, finding different size squares on a geoboard, the angles formed by the hands of a clock, and questions related to three consecutive integers. (MP)

Instructions are given for the use of worksheets whose objectives are to challenge and develop spatial visualization through the mental folding, rotating, and intersecting of cubes. (MP)

Topics discussed are: triangular numbers; three proofs of the surface area of a sphere; reverse notation; highest common factors; square roots from a graph; and clock geometry. (MP)

This paper discusses the process of investigating a mathematical situation, making conjectures, formulating an equation, then using mathematical induction to show the result is valid. Several examples appropriate for secondary school level are given. (DT)

Annual records of the one-mile sun can be used to introduce a variety of statistical ideas including the scatter diagram, theoretical vs. observed values, and normal equations. (SD)