The third in a series of four articles, this is concerned with establishing the main properties of the general linear transformation of the plane, equations of lines, area, and change of axes. For earlier articles, see MT number 57, Winter 1971, pp. 14-19 and MT number 58, Spring 1972, pp. 49-55. (DT)

A discussion of the so-called rose curves defined by simple trigonometric functions in polar coordinates. (MM)

This article presents some easily stated but unsolved geometric problems. The three sections are entitled: Housemoving, Manholes and Fermi Surfaces" (convex figures of constant width), Angels, Pollen Grains and Misanthropes" (packing problems), and The Four-Color Conjecture and Organic Chemistry." (MM)

Conditions for congruency of triangles are investigated. (DT)

Discusses a conjecture of a ninth-grade student that extended a geometry theorem about trisecting sides of a triangle. Presents a proof and extensions. (MKR)

Describes how a 3-inch by 5-inch card can be used to develop properties of similar triangles and prove the Pythagorean theorem. (MKR)

Presents interesting investigations and activities for inscribed and escribed circles of right-angled triangles. (ASK)

Around 300 BC, Euclid wrote "The Elements", a major treatise on the geometry of the time, and what would be considered "geometry" for many years after. Arguably "The Elements" is the second most read book of the western world, falling short only to The Bible. In his book, Euclid states five postulates of geometry which he uses as the foundation…

This book is loaded with hands-on measurement and geometry activities that will get students rolling up their sleeves, excited to use their math skills. The author has created these activities to supplement a teacher's existing math curriculum. They are flexibly designed for use as either introductory, reinforcement, or assessment activities. This…

In this article, the author uses a range of simple materials to facilitate students' understandings of measurement concepts. The six activities presented are essentially about looking at different configurations of a given volume. (Contains 6 figures.)

This note presents geometric and physical interpretations of the sufficient condition for a critical point to be a strict relative extremum: f[subscript xx]f[subscript yy] - f[superscript 2][subscript xy] greater than 0. The role of the double derivative f[subscript xy] in this inequality will be highlighted in these interpretations. (Contains 14…

The purpose of this research is to construct a conceptual framework for use in capturing students' unstable perception regarding the establishment of the universality of propositions through experimentation/measurement in school geometry. As a conceptual framework, this research uses a quadrangular-pyramid model comprised of five representative…