Presents an activity using quilts for many mathematical investigations. Benefits arising from the use of quilts include being useful, visually appealing, steeped in history, and an integral part of many cultures. (ASK)

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

Presents an activity on soap-bubble geometry using a guessing contest, explanations, and demonstrations that allow students to mesh observation and mathematical reasoning to discover that mathematics is much more than just number crunching. (ASK)

Introduces a room air-exchange activity designed to assess student understanding of the concept of volume. Lists materials for the activity and its procedures. Includes the lesson plan and a student worksheet. (KHR)

Describes how the concept of similar triangles was taught using an optical method of estimating large distances as a corresponding activity. Includes the derivation of a formula to calculate one source of measurement error and is a nice exercise in the use of the properties of similar triangles. (Author/NB)

Explains how conic sections can be approximated by paper-folding activities and proves why they work. (Author/NB)

Presents an active way for students to learn about SAS, SSS, ASA, AAS, and HL in determining congruent triangles. (Author/NB)

Suggests an alternative proof by analytic methods, which is more accessible than rigorous proof based on Euclid's Elements, in which students need only apply standard methods of trigonometry to the data without introducing new points or lines. (KHR)

Presents Cevian geometry problems (involving a segment that joins a triangle's vertex to a non-vertex point on opposite side) that illustrate how to implement methods for developing flexible strategies of problem solving, finding multiple representations, and making connections to other areas of mathematics and the real world. (ASK)

Describes ways to examine leaf structure and shape using fractal geometry. Students can test hypotheses using the leaves of replicated plants to look for non-linear trends in leaf shape along the stems of plants, across species, and under different environmental growth conditions. (SAH)

Presents four related problems that provide examples of ways to include justifications of interesting mathematics in courses taught prior to a geometry course. (ASK)

Describes an activity on fractal geometry in which students built a 19-foot-tall Sierpinski pyramid in the Minneapolis Convention Center in conjunction with the National Council of Teachers of Mathematics' (NCTM) 75th Annual Meeting in April, 1997. Contains 13 references. (ASK)

Features a brief description of fractals and their characteristics, some example activities, and an argument for including fractals in the mathematics curriculum. (ASK)

Geometrical representations can help students generalize arithmetic to algebra. Includes several examples including triangle numbers and models of cubes. (Author/MM)

Presents attributes of different types of software including Logo, geometric packages, graphical packages, and spreadsheets, each of which offers different opportunities for learning. Investigates the different ways in which the software allows for performing the given task so as to make the mathematics of the task explicit to users. (KHR)