The Prerequisites for Teaching Solid Geometry with GeoGebra Temel KÖSA Karadeniz Technical University Trabzon, Turkiye

Within these computer medium, The expression of dynamic geometry software is common name of the special geometry software such as Cabri Geometry and Geometers’ Sketchpad. Within these computer medium, geometric objects can be created on the computer screen, manipulated by the aid of mouse easily, Some measurements such as length, area and angle can be made on the geometric objects.

Three-dimensional Euclidian geometry is not a popular subject nowadays Three-dimensional Euclidian geometry is not a popular subject nowadays. One of the main reasons for this is that the diagrams and presentations of three-dimensional objects on geometry books are difficult to interpret for students. As it was met the need for students a better understanding by dynamic geometry software for plane geometry, it is essential to meet the need for solid geometry.

There have already been some special geometry packages to teach solid geometry such as Poly, Geometria, Cabri 3D and etc. But these software have also some limitations. For example, we can see only the nets and closed forms of solids in Poly or rotate solids and get some measurements in Geometria. Althought, we can do many things in Cabri 3D, we cannot cut a sphere with a plane to show a cap of sphere, or construct a three-dimensional object with loci.

Besides, there has been an available version of GeoGebra 3D Besides, there has been an available version of GeoGebra 3D. But this version is not sufficient features to teach Solid Geometry. It provides us to do vectoral operations and show some solids from different view points. GeoGebra3D

For the teaching Solid Geometry with GeoGebra, there should be some characteristic features. GeoGebra should provide; a set of primitive objects (point, line, segment, circle, polygon, plane and etc.) to construct geometric objects, a set of elementary operations (intersecting lines and planes, parallel and perpendicular lines and planes, joining the points to construct an object, and so on) for constructing geometric objects, to users to construct some geometric object (cube, sphere, cone, cylinder and etc.) as temple. to construct some geometric objects (prisms, pyramids, polyhedrons and etc.) with primitive objects and elementary operations.

GeoGebra should provide; to make some measurement (length, area, volume, angle, etc.) and have a calculator to calculate. to see the geometric object from different viewpoint (front, top, bottom side, and etc.). to cut the geometric object (polyhedron, cone, sphere, etc) with a plane. to see different nets of the geometric objects (prisms, pyramids, cone, polyhedron and etc.) when it is opened on a plane. to construct a three-dimensional object with loci.

Of course, many features can be uttered that a three- dimensional dynamic geometry software should have. GeoGebra team should take into consideration some important features in order to teach Solid Geometry effectively in a GeoGebra3D environment.

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