The author responds to a lecture given by Dieudonne, reported in the September 1973 issue of this journal, by considering the goals for mathematics instruction and by defending the selection of content and approaches for geometry, algebra, and trigonometry. (DT)

By introducing elementary trigonometry earlier in a geometry course, a teacher can demonstrate how a variety of techniques can be brought to bear on the same problem. Eight theorems illustrate this. (Author/KM)

Complex numbers and trigonometry are used to prove that a given constructed line is equal to the length of one side of a regular pentagon inscribed in a unit circle. (MP)

A game for the HP-25 programable calculator is discussed. The objectives of the game are to introduce angle measurement and the rudiments of trigonometry. A program for the game is given. (MP)

This article describes a model icosidodecahedron made from cardboard and used as a lampshade. (MM)

Theorems about the hyperbola which are ordinarily introduced in calculus courses can be proved without using the calculus. (SD)

In this article, a continuation of SE 513 148, the author presents seven additional applications of group theory to high school mathematics. These applications can be used, not only to illustrate the group concept, but also to extend the development of ideas in the high school curriculum. (SD)

A class of triangles related to the Pythagorean triangles is described; theorems concerning this class are proved. (SD)

The author argues that sine, secant, and tangent should be taught as the three basic trigonometric functions rather than sine, cosine, and tangent. (SD)

Several geometric and trigonometric proofs are discussed. These proofs were selected from a larger group because of their instructional value promoting enrichment or generalization. (SD)

The use of paper folding to study properties of geometric solids is discussed. (SD)

This course is part of an engineering certification program for men inspecting construction projects. It presumes some high school training in mathematics and science. The course begins with examples showing the importance of mathematics on the job. Following that is a section on algebra, one on geometry, and one on trigonometry. (KM)

Teacher tips are presented concerning geometry laboratory work, mathematics history, development of problem situations, and use of transparencies in graphical exercises in secondary school mathematics classes. (JG)