| 摘要 |
PURPOSE: A drawing protractor is provided to integrate various tools so as to be used in overall diagram studying classes. CONSTITUTION: The drawing protractor has a reference ruler. The reference ruler is attached bellow the protractor and is pivoted on the center of the protractor. The reference ruler is scaled and has a lot of holes at regular intervals. Drawing a line, protracting angle, drawing various types of figures, etc. are possible.
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