. The elements of railroad engineering . 691. If two angles have their sidesparallel and lie in the same or in oppo-site directions, they are equal. Thus,if the side A B, Fig. 20, is parallel tothe side D E, and if the side B C isparallel to the side E E, then the angleE = the angle B. Fig. 692. If two sides of anangle are perpendicular totwo sides of another angle,the two angles are , ii DE and G Ef, , are perpendicular toB A, and E E and Ef K areperpendicular to B C, thenwill angle E = angle B =■angle //. EXAMPLES FOR PRACTICE. 1. In a pulley with five arms, what part of
. The elements of railroad engineering . 691. If two angles have their sidesparallel and lie in the same or in oppo-site directions, they are equal. Thus,if the side A B, Fig. 20, is parallel tothe side D E, and if the side B C isparallel to the side E E, then the angleE = the angle B. Fig. 692. If two sides of anangle are perpendicular totwo sides of another angle,the two angles are , ii DE and G Ef, , are perpendicular toB A, and E E and Ef K areperpendicular to B C, thenwill angle E = angle B =■angle //. EXAMPLES FOR PRACTICE. 1. In a pulley with five arms, what part of a right angle is includedbetween the center lines of any two arms ? Ans. | of a right angle. 2. If one straight line meets another straight line so as to form anangle equal to If right angles, what part of a right angle does itsadjacent angle equal ? Ans. | of a right angle. 3. If a number of straight lines meet a given straight line at a givenpoint, all being on the same side of the given line, so as to form sixequal angles, what part of a right angle is contained in each angle ? Ans. g of a right angle. PLANE FIGURES. 693. A surface has only two dimensions: lengtJi andbreadtJi. 694. A plane surface is a flat surface. If a straightedge be laid on a plane surface, every point along thelementsofrailro01inte
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
