Watch Triangles

An analysis of the structure of the Eiffel Tower provides an opportunity to introduce the properties of triangles and the reasons they are so important in structural engineering. Geometric concepts related to congruent, equilateral and isosceles triangles are displayed and analyzed on the TI-Nspire. In a second section, the geometry of triangular sails is analyzed. Exercises on the TI-Nspire illustrate that a right angle triangle provides the greatest area in sail design. Other graphic illustrations demonstrate the functions of aspect and tangent ratio and the relationship of geometry to trigonometry.