Dissection of a Parallelogram into Triangles, Ross Surface Form #9

Description
This is the ninth in a series of models of plane figures (surface forms) designed by William Wallace Ross, a school superintendent and mathematics teacher in Fremont, Ohio. The unpainted wooden parallelogram (rhomboid in Ross’s terminology) is bisected along a diagonal into two scalene triangles. A paper label attached to the model reads: Rhomboid A 4x6 Bisected. According to Ross, the model shows that if a rhomboid (parallelogram) is cut diagonally through the opposite acute angles, two equal obtuse-angled triangles result.
Compare models 1985.0112.190 through 1985.0112.202. For further information about Ross models, including references, see 1985.0112.191.
Location
Currently not on view
Object Name
geometric model
date made
ca 1895
maker
Ross, W. W.
Physical Description
wood (overall material)
Measurements
overall: 1 cm x 20 cm x 15 cm; 13/32 in x 7 7/8 in x 5 29/32 in
place made
United States: Ohio, Fremont
ID Number
1985.0112.197
catalog number
1985.0112.197
accession number
1985.0112
subject
Mathematics
Science & Mathematics
Arithmetic Teaching
See more items in
Medicine and Science: Mathematics
Arithmetic Teaching
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Wesleyan University

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