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)

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

Presents activities to demonstrate some of the properties and relationships among the Platonic polyhedra. (ASK)

Presents an activity that uses an inexpensive paper plate and a short length of adding machine tape to help students experience the concept of radian measure. Focuses on radian measurement and connects many geometric concepts regarding the circle. (ASK)

Outlines a geometry task that uses computers to transform some quadrilaterals into other quadrilaterals. (ASK)

Helps students identify the animal that corresponds to the year of their birth according to the Chinese zodiac. Defines the structure of the Chinese zodiac so that the subsets of compatibles and opposites form closed substructures with interesting mathematical properties. (ASK)

Provides classroom suggestions for combining numerical, algebraic, and geometric techniques with the understanding of a simple method for computing square roots. Historical origins of the method illustrate the debt owed to ancient minds living in what are now India, Pakistan, Iraq, and Egypt. (Author/NB)

Presents an activity that focuses on the features of ellipses and the concepts of limit and infinity. (ASK)

Presents an activity that uses square-foot tiles as a coordinate system on which human geometric models are constructed. (ASK)

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

Describes a classroom inquiry into expressing the number pi as the limit of a sequence of different ratios using relationships among coins and the radius of an inscribed circle. (KHR)

Demonstrates that the equation of a circle (x-h)2 + (y-k)2 = r2 with center (h; k) and radius r reduces to a quadratic equation x2-2xh + (h2 + k2 -r2) = O at the intersection with the x-axis. Illustrates how to determine the center of a circle as well as a point on a circle. (Author/ASK)

Presents a mathematics lesson that focuses on particular connections between geometry and measurement, how change in shape effects the area of the interior region of parallelograms with the same perimeter. (ASK)

This paper describes a classroom, instructor-led activity designed to show how graphic calculators can be used to explore coordinate geometry. The activity involves digitizing an image of a hand and transforming the image through geometrical transformations. Teaching notes and calculator instructions are included as are blackline masters. Also…

Presents a discovery activity that connects mathematics and the world of entertainment. Combines geometric transformations with a calculator's DRAW, MATRIX, and PRGM features to generate visual reinforcement of mathematical concepts. (Author/NB)