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如图1,一个几何体的正视图、侧视图和俯视图均是等腰直角三角形且腰长为1,则该几何体的外接圆的表面积为().(A)12π(B)4(3~(1/2))π(C)3π(D)12(3~(1/2))π解决这类问题的关键点在于如何由三视图还原立体图形.本题的难点在于侧视图,很多同学不能想象出在具体立体图形中会呈现出怎样的几何关
(A) 12π (B) 4 (3 ~ (4)) (1) The front view, side view and top view of a geometry are isosceles right triangle and waist length is 1, The key point to solve this kind of problem lies in how to restore stereoscopic graphics from three views.The difficulty of this problem lies in the side view and many students can not Imagine how the geometry will appear in a particular stereo