试解

来源: monseigneur 于 2026-05-23 19:05:47 [] [旧帖] [给我悄悄话] 阅读数 : (471 bytes)
回答: 再来一题 由 贫论贫论 于 2026-05-22 09:21:41

add another two similar lines, to arrive at the 4 shaded triangles. Obviously, the hollow center square is of the same area as the 4 shaded triangles added up. Hence, the area in question is simply the area of any shaded triangle, such as DFG.

DFG is similar to DEC, whose area is 25. DE= 5*sqrt(5). DF/DE=sqrt(5). 

Hence, sDFG/sDEC=1/5. sDFG = 5.

 

所有跟帖： 

• insighted from your great solution -皋诚- ♀ 给 皋诚 发送悄悄话 (47356 bytes) () 05/23/2026 postreply 19:41:41

• 眼花缭乱：-）感觉所有区块的面积都被算出来了 -monseigneur- ♂ 给 monseigneur 发送悄悄话 (0 bytes) () 05/23/2026 postreply 20:33:49

• 这两条线画了就很清楚，当中的正方形面积是20 -贫论贫论- ♂ 给 贫论贫论 发送悄悄话 (0 bytes) () 05/24/2026 postreply 16:09:10

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