Worthen, William Ezra, 1819-1897, [from old catalog] ed · New York, Appleton · leaf 22
and that the arcs can therefore betaken as the measures of angles. For thispurpose the whole circumference is supposedto be divided into three hundred and sixty de-grees (360°), each degree subdivided into sixty minutes (60), and each minuteinto sixty seconds (60). Each right angle has for its… … A B E- Fig. 10.
Mechanical drawing
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