Safe-T 45779 Blackboard Protractor


This oversized white plastic semicircular protractor may be used at a chalkboard or whiteboard. A smaller semicircle is cut out of the protractor's interior. Three curved grooves form a third semicircle between these two semicircles. The protractor is divided by single degrees and in three rows of divisions. It is marked by tens from 0° to 180° (left to right) and from 180° to 0° (right to left).

An oversized ruler, or scale of equal parts, divided to mm and marked by single cm from 1 to 10, is on the diameter of the innermost semicircle. A notch for the origin point of the protractor is at the center of this edge. Another scale of equal parts, divided by 16ths of an inch and marked by ones from 1 to 6, is along the outer lower edge.

The protractor is marked: Angles Opening Left (>) Use Upper Scale; Angles Opening Right (<) Use Lower Scale (/) SAFE-T PROTRACTOR® #45779. A recycling logo for plastic type 6 appears in the lower right corner. The protractor retailed for approximately $13 in 2011.

See also ID numbers 1998.0033.02 and 1999.0117.02.

Date Made: ca 2000Associated Date: 2000

Associated Name: Extra Measures, Inc.Maker: Safe-T Products, Inc.

Location: Currently not on view

Place Made: United States: Illinois, La GrangeAssociated Place: United States: Illinois, Bensenville

Subject: MathematicsProtractorEducation


See more items in: Medicine and Science: Mathematics, Science & Mathematics, Protractors


Exhibition Location:

Credit Line: Gift of Extra Measures, Inc.

Data Source: National Museum of American History

Id Number: 2000.0160.03Accession Number: 2000.0160Catalog Number: 2000.0160.03

Object Name: protractor

Physical Description: plastic (overall material)Measurements: overall: 1.5 cm x 47.5 cm x 30.6 cm; 19/32 in x 18 11/16 in x 12 1/16 in


Record Id: nmah_904391

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