Geometric Model, Ruled Surface in Cylinder

Geometric Model, Ruled Surface in Cylinder

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Like several other models made by the Jesuit mathematician Joseph F. MacDonnell of Fairfield University, this model shows a surface swept out by a moving straight line. Such a surface is called a ruled surface. It is represented by the cylindrical coordinates (r, t, z) by the equation r = a + z tan (pt/q). The model has a clear plastic cylindrical exterior, with pink plastic threads inside it that represent the surface. Here the ratio p/q = 3/2 and the fraction 3/2 is marked on the outside of the cylinder.
Currently not on view
Object Name
geometric model
MacDonnell, S.J., Father Joseph
place made
United States: Connecticut, Fairfield
Physical Description
plastic (overall material)
overall: 25.5 cm x 10.2 cm x 10.2 cm; 10 1/32 in x 4 1/32 in x 4 1/32 in
ID Number
nonaccession number
catalog number
Credit Line
Gift of Father Joseph MacDonnell, S.J.
See more items in
Medicine and Science: Mathematics
Data Source
National Museum of American History
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