The study of the rotational symmetries of the regular polyhedra is important in the classroom for many reasons. Besides giving the students an opportunity to visualize in three dimensions, it is also an opportunity to relate two-dimensional and three-dimensional concepts. For example, rotations in R[superscript 2] require a point and an angle of…

In this short note is presented an easy and instructive proof of l'Hopital's Rule in both the 0/0 and [infinity]/[infinity] cases, obtained by translating the theorem into a simple geometric statement about paths in the plane. (Contains 4 figures.)

A previous note described how complex numbers can be used for elementary analytic geometry in the plane, describing lines, circles and their intersections using complex Cartesian equations. In the present note, a description of elementary plane transformations, namely homotheties and translations, their group structure and their operations on…

In this article, an attempt is made to find all linear transformations that map a standard Pythagorean triple (a Pythagorean triple [x y z][superscript T] with y being even) into a standard Pythagorean triple, which have [3 4 5][superscript T] as their fixed point. All such transformations form a monoid S* under matrix product. It is found that S*…

This textbook presents definitions and remarks, axioms, properties of polygons, ratios and proportions, planes and their angles, measurement of areas and proportions of figures, solids, and mensuration of surfaces, solids, and round bodies.

A number of different solutions are presented and discussed for the problem of constructing a unit segment given the length of the square root of X. (DT)

This paper on classroom factors influencing students' proof construction ability reports findings from the data collected in the first two years of a three-year National Science Foundation (NSF)-funded project. Four different classrooms, two from each participating school, were involved in the project. Data sources included videotaped classroom…

Since all manner of quantities require to be compared together, in mathematical computations, and their various relations searched out and determined and as most of our knowledge in mathematical subjects depends on the proportions of several things to one another: so it is requisite that the nature of proportion, and the methods of reasoning…

This work is chiefly a compilation from other books; and but very little new is added except a more full explanation, than has yet been published, of rectangular surveying, or the method of calculating the area of fields arithmetically, without drawing a plot of them and measuring with a scale and dividers, as has been the common practice; and…