model_size 34 x 17,5 x 19
model_weight 500
model_catalognum 151/ 39
model_objectnum 97619-000
model_originalprize 78 DM
model_since 1958.
model_externallinks Description in the catalogImage in the catalog
model_from :
nav_classification
The ellipse as orthogonal projection of a circle
The model includes a semi-circle that can be rotated about a diameter. By means of two supporting triangles the semi-circle may be fixed in such a position, that it's orthogonal projection is an ellipse. "
The construction of points of the ellipse from points of the circle and the affine correspondence between the major auxiliary circle and the ellipse is to be seen.