Advantages of representing ternary and quaternary composition diagrams by means of rectangular coordinates were pointed out in a previous paper (EJ 288 693). A further advantage of that approach is that analytic geometry, based on rectangular coordinates, is directly applicable as demonstrated by the examples presented. (JN)

Included in this section are brief articles on drawing altitudes of triangles, sketching parabolas, and visualizing variability. (MNS)

Presents an activity in which students estimate the weight and volume of one million dollars in notes and coins of various denominations. Also presents several geometry activities. Student worksheets for the activities are included. (JN)

A proof is given concerning the intersection of the medians of a triangle, then the problem is generalized and discussed. (DT)

Different methods for doing five basic geometric constructions are described. (DT)

The problem "Given three planar points, find a point such that the sum of the distances from that point to the three points is a minimum" is discussed from several points of view. A solution that uses only calculus and geometry is examined in detail. (MNS)

Considers the electrostatic problem of a point charge in a domain bounded by conducting planes. Lists all such domains for which a solution by images exists, describes the image charge arrays in familiar crystallographic terms, and gives an illustrative example. (Author/GS)

This activity involved constructing parallelograms on the sides of an arbitrary triangle and discovering a relationship between the areas of the parallelograms. (MP)

Presents a classroom scenario in which a student concocts a unique solution to a standard circle exercise and the class attempts to verify if the solution works for all cases of the problem. (MKR)

Discusses assumptions implicit in any system of measurement. Describes a three-rectangle problem designed to help children explore additivity of areas and relationships between area and shape. Suggests ideas for action research. (FDR)

Explains standard drawing layouts and rules for creating orthographic and isometric views of a three-dimensional object. Normal and inclined surfaces are also discussed. Concludes with recommended classroom activities. Includes reproducible student worksheets. (FDR)

This model is useful in identifying specific learning problems and in providing techniques for the teacher to motivate and teach students at all levels. What it is and how it can be used are discussed, illustrated by specific strategies for geometry and science. (MNS)

Integrates different geometries and blends several topics that have important applications in both higher mathematics and other disciplines. Aims to make these topics more attractive and understandable to high school students in a way that reinforces logical thinking with visual understanding obtained through computer usage. Contains 28…

Presents a unit to review geometric concepts and problem solving by having students work cooperatively to discover geometric shapes constructed from two congruent right triangles obtained from cutting a rectangle along its diagonal. Students report their findings both orally and in writing. (MDH)

Describes activities that use the geometric construction capabilities of the Geometer's Sketchpad computer software to explore triangles. Topics investigated include angle measurement, the sum of the measures of the angles of a triangle and a five-pointed star, triangle classification, and area and perimeter of a triangle. (MDH)