. Practical mathematics : an elementary treatise covering the fundamental processes of arithmetic, algebra, and geometry, with a practical presentation of logarithms and curve plotting. PRACTICAL MATHEMATICS 101 90°. 90° while one-half, two-thirds, andone-third of a right angle would rq>_resent angles of respectively 45°J60°, and 30°, as shown in Fig. Drawing Work, it will be foundthat the 45° triangle and the 30°— 60° triangle are useful articlesof equipment, but when it comesto accurate values of angles, somedevice like a protractor, Fig. 14,showing degrees and fractions of de-grees
. Practical mathematics : an elementary treatise covering the fundamental processes of arithmetic, algebra, and geometry, with a practical presentation of logarithms and curve plotting. PRACTICAL MATHEMATICS 101 90°. 90° while one-half, two-thirds, andone-third of a right angle would rq>_resent angles of respectively 45°J60°, and 30°, as shown in Fig. Drawing Work, it will be foundthat the 45° triangle and the 30°— 60° triangle are useful articlesof equipment, but when it comesto accurate values of angles, somedevice like a protractor, Fig. 14,showing degrees and fractions of de-grees, is necessary. Each degree isdivided into 60 equal parts called minutes, , and each minute into60 equal parts called seconds, . Thus to represent an angle of 23degrees, 47 minutes, and 9 seconds, write 23° 47 9. The relations of these units may be summarized as follows: 60 seconds () = 1 minute () 60 minutes = 1 degree (°) 360 degrees = 1 circle Two angles are complementarywhen their sum is equal to one rightangle or 90°; they are supplementwrywhen their sum is equal to two rightangles or 180°. Thus, an angle of
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmathematics, bookyear
