The computer should be equipped with “Spherical Easel” which can be downloaded from. One computer is needed for each group of three students. To utilize the spherical easel tool to make other explorations and discoveries. To construct a spherical triangle and to notice the differences in the properties of planar and spherical triangles.ħ. To construct a two sided polygon on the sphere and to determine that although a two sided polygon does not exist in planar geometry, it does exist in spherical geometry.Ħ. To determine that parallel great circles do not exist.ĥ. It is analogous to a line in planar geometry.Ĥ.

To construct a great circle and to determine that it is the simplest line in spherical geometry. Each spherical point determines an opposite point on the sphere.ģ. To construct a spherical point and to determine that a spherical point is analogous to a point in Euclidean geometry. To recall that a sphere is a three-dimensional surface in which all points are equidistant from a fixed point.Ģ. They will be able to compare and contrast the two-dimensional objects to the three-dimensional objects.ġ.

Through exploration, students will gain knowledge of the properties of some objects in spherical geometry. Students will be able to use the Spherical Easel technology tool to form different geometric objects on the surface of a sphere.

Principles & Standards for School Mathematics Geometry Standard for Grades 9-12: “Analyze characteristics and properties of two-and three-dimensional geometric shapes and develop mathematical arguments about geometric relationships” (NCTM, 2000, p. Unit on Spherical Trigonometry: Day 1 Lesson Plan

Spherical geometry khan academy