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第十一册长方体和正方体的认识这一单元中,几次提到了横截面的概念。如:练习二十五的第8题:一根长方体木料,它的横截面的面积是(1/25) 平方米……练习二十六的第4题:一段方钢,长2米,横截面是一个边长为5厘米的正方形……98页的例7…………在计算堤坝和沟渠的土、石方时,通常先算出横截面的面积……究竟什么是横截面?课本上没有讲,参考书也没有提到,这似乎是不言即明的概念了。其实不然,我
The Eleventh Volume A Perspective on Cuboids and Cubes This unit mentions the concept of cross sections several times. Such as: Practice twenty-five eighth questions: a rectangular parallelepiped timber, its cross-sectional area is (1/25) square meters ... Exercise twenty-six fourth questions: a section of steel, 2 meters long, horizontal Section is a square with 5 cm sides ... Example 98 on page 98 ............ When calculating the earth and stone of dams and ditches, the area of the cross section is usually calculated first ... what is the cross section? Without a word, the reference book also did not mention it, which seems to be an outspoken concept. Actually not, me