Talk:Spherical Easel Exploration

Instructor Notes

Note that the problem concerning the area of a triangle works best when taken as a "dynamic problem". I.e. Construct the altitudes of the triangle (use the perpendicular option in the construction menu) and use the calculator to compute the three versions of the .5*(base)*(height) formula. If you then use "move" to manipulate the triangle the .5*(base)*(height) formula will show more divergence when the triangles get larger. This is of course due to the fact that the sphere is locally approximately flat. So small triangles do not show the problem with the .5*(base)*(height) formula as clearly. --Barta 09:43, 15 October 2007 (CDT)

There are two explorations that use spherical easel. This is one, and Spherical_Geometry:_Polygons is the other. Both do many things, and both do many of the same things. I'd like to take these two and turn them into two explorations that are a bit more focussed. One should really hit on the triangles, and the angle sum >180, defect, etc. The other can look at quads and other spherical geometry questions. I'm not doing it this year, but I'd like to in the future. Bryan (talk) 11:01, 27 October 2014 (CDT)