Investigated here are some of the results which can be obtained using the double-sided straight edge. Seventeen possible constructions are presented with solutions or partial solutions given to most. (MP)

Described is a method of teaching geometric constructions. The method relates five basic constructions to the properties of a rhombus. (RH)

Archimedes viewed the method of centroids as a valuable tool for intuitive discoveries. This article presents several uses of this technique and discusses how the method of centroids could be used in secondary schools. (Author/MK)

A system of area measurement developed for the isometric geoboard is used to justify some relationships that are often proved using square units of area. (Author/MK)

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)

The relationship between area and perimeter is presented through a series of laboratory-type activities and demonstrations. (SD)

PRESENTED IS A FUSED COURSE IN PLANE, SOLID, AND COORDINATE GEOMETRY. ELEMENTARY SET THEORY, LOGIC, AND THE PRINCIPLE OF SEPARATION PROVIDE UNIFYING THREADS THROUGHOUT THE TEXT. THE TWO CURRICULUM GUIDES HAVE BEEN PREPARED FOR USE WITH TWO DIFFERENT TEXTS. EITHER CURRICULUM GUIDE MAY BE USED DEPENDING UPON THE CHOICE OF THE TEACHER AND THE NEEDS…

The proof is given that, if three equilateral triangles are constructed on the sides of a right triangle, then the sum of the areas on the sides equals the area on the hypotenuse. This is based on one of the hundreds of proofs that exist for the Pythogorean theorem. (MP)

This article, written by a high school junior, shows that there can never be more than two isosceles triangles having the same perimeter and area. (MK)

The activities are designed to have students manipulate physical models of geometric figures, engage in spatial visualization and observe relationships between triangles and parallelograms and between triangles and rectangles. Worksheets designed for duplication are included in the materials and an answer key is provided. (MP)

The material examines areas generated by combinations of: (1) Circles and Triangles; (2) Closely Packed Circles; and (3) Overlapping Circles. The presentation looks at examples of certain areas and at logical ways to generate the necessary algebra to clarify the problems and solve general cases. Ideas for extension are provided. (MP)

This is one of a series of geometry modules developed for use by secondary students in a laboratory setting. The authors of this sequence of modules have chosen not to cover the initial basic postulates and theorems since they can be found in nearly every geometry text. Instead, a list of necessary postulates and their consequences is included. It…

Establishes that the congruence criteria for polygons with more than three sides (such as ASASA for Quadrilaterals) are easily proved within the scope of the standard high school geometry course. Also argues that elegant applications of these criteria are more easily found once these new criteria are known. (PK)

A program is outlined for the treatment of Tessellations. Major topics are: Introduction; Tessellations; Regular Tessellation; Semi-Regular Tessellations; Nonregular Tessellations; and Miscellaneous Tessellations and Filling Patterns. (MP)

This is one of a series of geometry modules developed for use by secondary students in a laboratory setting. This module, intended to present a treatment of congruent triangles which is not totally axiomatic, contains six sections: (1) Draw vs. Construct; (2) Triangle Construction; (3) Arguing for Congruence; (4) Parallel Line Construction; (5)…