This monthly column contains teaching suggestions on: using codes to convey information, flow proofs in geometry, and volleyball and probability. (MP)

A classroom activity is illustrated in which vectors are drawn in the first quadrant of a rectangular coordinate system forming a vector polygon which is then reflected about each axis. (MN)

An elementary knowledge of geometry is shown to be helpful in problem solving, especially in that the shortest distance between two points is a straight line. (MN)

The technique of organizing data in tables to solve counting problems in geometry is illustrated in the solution of five problems. (MN)

The author has selected a number of episodes that illustrate some of the successes and failures of humanity's attempt to find the area of the circle and presents them as problem studies. (MN)

Topics for student projects in geometry are discussed; useful references are included. (JT)

Relationships between elementary analytic geometry and several types of number sequences are discussed. (JT)

Geometry and a hand-held calculator are used to find a value of pi accurate to five decimal places. (CP)

This article provides a manipulative demonstration of the relationship between the squares on the sides of a right triangle. Materials are listed and directions are given for the student. Illustrations are included. (Author/MA)

Activities involving copying, enlarging, and translating stick figures can enhance students' understanding of graphs. (SD)

The author recommends the use of flow charting to help students understand the manipulation of algebraic formulae. He identifies some problems with flow charts and suggests an alternative method of constructing flow diagrams. (SD)

Provided is an analysis of Turtle Geometry using van Hiele levels of development and understanding. The author also relates a language use framework, suggested by the work of Fry (1982), to the language activities of Turtle Geometry. Research supporting the analysis is discussed. (RH)

Describes the characteristics of the five levels of thinking in the hierarchical sequence postulated by the van Hiele theory, as well as several properties associated with each level of thinking. Also discusses some implications of the theory for the planning of geometry instruction in the classroom. (JN)

Discussed is an approach in which algebra and geometry are interwoven in a series of problems that develop one from another. The two main concepts are the algebraic concept of function and the geometric concept of the "family of quadrilaterals." (MNS)

Diagrams that aid in relating the golden ratio to pi are discussed, with the theorem and its proof. (MNS)