Davies, Charles, 1798-1876 · New York and Chicago, A. S. Barnes and company · leaf 95
AB4o or £C20 Sch. The last theoremmay be illustrated by de-scribing a square on the hy-pothenuse BC, equal to 5,also on the sides BA, A C,respectively equal to 4 and 3 ;and observing that the num-ber of small squares in thelarge square is equal to thenumber in the two smallsquares ■■ACT-BCf AC-AB4 … BOOK IV. 95 Of Triangle Sides cut Proportionally.THEOREM XIII. If a line be drawn parallel to the base of a triangle, it will dividethe other two sides proportionally. Let ABC be any triangle, and DE astraight line drawn parallel to the baseBC: then will AD : DB : : AE : EC.
Geometry · Plane trigonometry
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