Model for Descriptive Geometry by A. Jullien - Distance from a Point to a Plane

Suppose one is given plane APA’ and point (m, m’) not on the plane. To find the distance, one must find the perpendicular from the point to the plane. This is done by finding the shortest vertical and horizontal distances from the point to the plane. Segment mn on the horizontal plane is the projection of the shortest distance of point (m, m’) to the plane horizontally, often referred to as the perpendicular foot. Line de’ (red string) is the image of this foot up onto the plane. Likewise, segment m’n’ is the vertical perpendicular foot and its image on the plane is the wire coming out of the horizontal plane. Point (n, n’) where these two lines meet is the perpendicular from (m,m’) to the plane, and thus the shortest distance.
For more details, see COLL.1986.0885 and 1986.0885.01.01.
Currently not on view
Object Name
geometric model
date made
ca 1880
Jullien, A.
Physical Description
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
place made
France: Île-de-France, Paris
ID Number
catalog number
accession number
descriptive geometry
Science & Mathematics
Jullien Geometric Models
See more items in
Medicine and Science: Mathematics
Jullien Geometric Models
Data Source
National Museum of American History, Kenneth E. Behring Center

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