An activity unit is described that helps children recognize the inside and outside of closed curves. (MP)

The use of the Mira, a geometric device for studying reflections, is discussed. Proved are that all Euclidean constructions can be made with a Mira and that the Mira can be used to trisect an angle. (DT)

Describes three activities in discrete mathematics that involve coloring geometric objects: counting colored regions of overlapping simple closed curves, counting colored triangulations of polygons, and determining the number of colors required to paint the plane so that no two points one inch apart are the same color. (MKR)

Includes lesson plans and worksheets that deal with transformational geometry, specifically reflections. The lesson for grades three to four focuses on angles of incidence and reflection and that for grades five to six involves mirror images. (MKR)

Presents an activity in which students use geometric figures, rep-tiles, to design a tile floor. Rep-tiles are geometric figures of which copies can fit together to form a larger similar figure. Includes reproducible student worksheet. (MKR)

Presents an activity, involving pentagons and using a figure manipulator such as The Geometer's Sketchpad, that requires students to reason geometrically without making unsubstantiated assumptions based on diagrams. (MKR)

Archimedes' method for estimating the value of pi is developed and compared with the Gregory-Machin infinite series method. Programs for the TI-81 calculator for finding the upper and lower bounds using the classical method and estimating pi using infinite series are provided.(Author/MKR)

Presents activities with 10- and 4-straw flexigons, an object created by stringing together lengths of plastic drinking straws with nylon fishing line. Discusses several geometric theorems that can be demonstrated with flexigons. (MKR)

Presents a strategy for graphing conic sections on the polar plane without using a table of values by beginning with information gained from the graphs of circular functions. (MKR)

An exercise which relates particle scattering and the calculation of cross-sections to answer the following question--"Do you get wetter by walking or running through the rain?"--is described. The calculations used to answer the question are provided. (KR)

Recognizing geometric shapes and noting their special properties are important steps in learning geometry. Offers the use of geoboards and emphasizes that much of what teachers want students to learn about squares, rectangles, and trapezoids can be accomplished with geoboard figures. Presents activities on quadrilaterals using geoboards. (ASK)

This paper gives a broad descriptive account of some activities that the author has designed using Sketchpad to develop teachers' understanding of other functions of proof than just the traditional function of 'verification'. These other functions of proof illustrated here are those of explanation, discovery and systematization (in the context of…

This article was written as a result of the author reading "MT177," a special issue dedicated to the teaching of "proof" in mathematics. He used the ideas in this special issue for planning his session "mathematical reasoning and proof," which was part of a weekend course for primary trainees. It consisted of three activities: (1) How many…

In this article we describe a hands-on activity for a liberal arts mathematics course that focuses on the beauty and unity of mathematics. The purpose of the activity is to tie together several topics in the context of a "real-world" situation. These topics include: fractals, non-Euclidean geometry, symmetry, and Platonic solids. This activity…

Techniques that can be used in solving various mathematical problems are illustrated by an optimization problem and the accompanying model and solution. (MP)