The given lines are the black strings: ab’ and dc’. They intersect at (m, m’). Segment ad on the horizontal plane creates a triangle with the given lines as sides. Point n on the horizontal plane is perpendicular to ad through point (m, 0). By rotating the triangle about line ab onto the horizontal plane, point (m, m’) maps to point M2. Angle aM2d is the angle between the two given lines.
For more details, see COLL.1986.0885 and 1986.0885.01.01.
Currently not on view
paper (overall material)
metal (overall material)
overall: 6.5 cm x 7.5 cm x 6.5 cm; 2 9/16 in x 2 15/16 in x 2 9/16 in
This image is in the public domain (free of copyright restrictions). You can copy, modify, and distribute this work without contacting the Smithsonian. For more information, visit the Smithsonian's Open Access page.
International media Interoperability Framework
IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more.