Worksheets on constructing the circumcenter, the centroid, the orthocenter, the incenter, and the Nine-Point Circle in a triangle are provided for duplication. (DT)

The proof is given that, if three equilateral triangles are constructed on the sides of a right triangle, then the sum of the areas on the sides equals the area on the hypotenuse. This is based on one of the hundreds of proofs that exist for the Pythogorean theorem. (MP)

This article, written by a high school junior, shows that there can never be more than two isosceles triangles having the same perimeter and area. (MK)

Directed graph theory is used to find the number of ways of building a rectangular parallelepiped from six rectangular boards using simple overlap joints. (MM)

Reports a proof of a classical geometry problem. The proposition is - In any triangle there are two equal sides, if the angles opposite these sides have angle bisectors with equal lengths. (RP)

A proof is given of a construction axiom, involving the use of a Mira used to construct a segment of a length cube root of K when segments of lengths 1 and k are given. (MP)

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)

Research has shown that affordances of computers may be exploited in the design of mathematical tasks so as to provide interesting and challenging activities. At the same time, opportunities for learning mathematics may be constrained if the design of the task is not appropriate. A tool which allows teachers, researchers and task designers to…

The authors derive distance formulas in two-and-three-dimensional coordinate geometry utilizing the concept of similar triangles and the Pythagorean theorem. (MN)