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我在校办工厂劳动时,工人师傅问我,把梯形的铁板剪成面积相等的几份(每块一份,不能几块拚成一块),应如何画线?我推导出下面的公式一,由类比联想又推出公式二、三。一、设梯形的上、下底分别为a、b,高为h,作直线平行于梯形的底,把梯形分为两部分,上部分的面积为梯形面积的m/n。则上底与截线的距离。证明:如图1,延长梯形的两腰交点为P,设△PAD的高为x,则
When I was working in a factory and the factory was working, the worker asked me to cut the trapezoidal iron plates into several equal parts (one for each piece, not for a few pieces). How should I draw lines? I derived the following formula First, Formula 2 and 3 are introduced by analogy. First, set the upper and lower bottoms of the trapezoid to be a and b, and the height is h. Make a straight line parallel to the bottom of the trapezoid. Divide the trapezoid into two parts. The area of the upper part is m/n of trapezoid area. The distance between the bottom and the cut line. Proof: As shown in Fig. 1, the two waist intersections of the extended trapezoid are P, and the height of △PAD is x.