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幼苗
共回答了13个问题采纳率:100% 举报
已知,∠ABE = α ,∠ACE = 2α ,∠ADE = 4α ,BC = 30 ,CD = 10√3 .
由 ∠BAC = ∠ACE-∠ABE = α = ∠ABC ,可得:AC = BC = 30 ;
由 ∠CAD = ∠ADE-∠ACE = 2α = ∠ACD ,可得:AD = CD = 10√3 .
设 AE = h ,DE = a ,则有:CE = a+10√3 .
由勾股定理,可得:AE2+DE2 = AD2 ,AE2+CE2 = AC2 ,
即:h2+a2 = 300 ,h2+(a+10√3)2 = 900 ,
解得:h = 25 ,a = 5√3 ;
即:建筑物的高度为 25 米.
1年前
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