A method for approaching the value of pi using a transparent sheet of parallel lines is discussed. (MP)

Using a geoboard to find polygons with given perimeters presents a problem which refines skills and provides an opportunity to inquire and discover. (MK)

Instructions are given for making a solid from unit cubes joined face to face. Activities lead to design and construction of the SOMA cube, along with other cube puzzles. (DT)

Presents methods for teaching two mathematical concepts that utilize visualization. The first illustrates a visual approach to developing the formula for the sum of the terms of an arithmetic sequence. The second develops the relationship between the slopes of perpendicular lines by performing a rotation of the coordinate axes and examining the…

A set of three worksheets is provided, along with a guide for the teacher. Using manipulative materials, students investigate the difference between the consecutive sums of the numbers along the three sides of a triangle. (MNS)

Presents a cooperative-learning lesson in which high school students visit stations equipped with different tools to establish the midpoint of a Pixy Stix, a brand of candy-filled straw. Provides solutions for two potential stations, suggestions to extend the activity, and two activity worksheets. (MDH)

Presents an activity to introduce students to the intrinsic curvature of surfaces using a wide variety of objects. Describes student discoveries, several variations on the project, and possible classroom discussion topics. A reproducible student worksheet and 17 references are included. (MKR)

Presents a series of 5 reproducible worksheets for grade levels 5-10 that provide hands-on activities to help develop the concept of slope. (MDH)

Presents a worksheet on graph paper that allows students to determine the perpendicular bisectors of given segments by folding the paper. Students then determine the slopes of the perpendicular bisectors and use inductive thinking to discover the relationship between the slopes of perpendicular lines. (MDH)

Discusses possible approaches to solving the problem of how many different triangles can be formed on an n x n geoboard and the different geometric concepts utilized to formulate a solution. Approaches include counting strategies, writing a computer program, and using difference equations. (MDH)

Presents activities that use visual-geometric models to help students develop their understanding of exponents and division of powers with the same base. Presents opportunities for students to discover patterns for themselves and communicate these findings to others. (MDH)

Presents activities that utilize representations of the side, front, and top views of three-dimensional configurations of blocks to develop spatial-visualization skills and aspects of the concept of function. Provides worksheets of these open-ended investigations. (MDH)

Presents a series of four worksheets to develop students' perception of spatial relationships. The tasks require students to use cubes to build models and describe the models by representing the front, right, and top views on grid paper. Provides reproducible worksheets. (MDH)

Presents activities to create designs with different arrangements of square tiles, which gives students an opportunity to make conjectures about perimeter and to make convincing arguments to justify those conjectures. Includes worksheets. (MKR)