On each side of a unit square,an equilateral triangle of side length 1 is constructed.On each new side of each equilateral triangle,another equilateral triangle of side length 1 is constructed.The interiors of the square and the 12 triangles have no points in common.Let R be the smallest convex polygon that contains R.What is the area of the region that is inside S but outside R?
A 1/4 B √2/4 C 1 D√3 E 2√3
Let R be the region formed by the union of the square and all the triangles,and let S be the smallest convex polygon that contains R.要有解答过程和讲解啊!谢谢!!~
where is the S?
Let R be the smallest convex polygon that contains R?
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选b:
理由,在等边三角形的外围在做等边三角形时,有两种状态,如图中所标1,2两种状态,像搭积木那样考证,只有如图所示的多边形面积S最小,因为除去正方形及12个三角形的面积之外,只多余了一个等边三角形的面积,其余的放法怎么都会使得多边形的面积除去固定值之外,比一个三角形的面积多。所以,本题所求的面积:S之内,R之外的面积是一个等边三角形的面积:B