Drafting Triangle

This 5-1/2" 20°-70°-90° wooden triangle has a 3/8" round hole at the center for positioning and holding the instrument. Compare to MA*304826.137, MA*335331, and 1979.0876.02. A previous user has written the numbers 20, 70, and 90 at the appropriate corners. For other drawing triangles with unusual angle measurements, see MA*334622 and 1990.0690.01. The Department of Mathematics at Brown University gave this object to the Museum in 1973.
Currently not on view
Object Name
date made
ca 1900
Physical Description
wood (overall material)
overall: 6.6 cm x 14 cm x .1 cm; 2 19/32 in x 5 1/2 in x 1/32 in
ID Number
catalog number
accession number
Drawing Instruments
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Squares and Triangles
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Brown University Department of Mathematics

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