abced这幅画是谁画的啊??
958188 2022-04-01 22:56 过D点做DH//CF交AB于点H所以 AE/ED = AF/FH (平行线分线段成比例定理) 因为 BD=DC,D优艾设计网_Photoshop论坛H//CF所以 BH=FH (平行线分线段成比例定理)所以 AE/ED = AF/FH = AF/(BF/2) =2AF/BF得证。
〥WaI〤 优艾设计网_PS问答 2022-04-01 23:01 过A点作AF垂直BD、AG垂直BC求证:△ABF与△AGE相似得到:AB:AE=AF:AG在△AGC中 AG =√3/2 AC=√3/2 AB在△AFD中 AD=5 AF=5/2√3答案:AB=√20
坚果123 2022-04-01 23:05 优艾设计网_平面设计 过D点作BF的平行线DG交AC与G, 设S(△AEF)=x,则由EF∥DG,且AE=ED可知,S(△ADG)=4x,即S(DEFG)=3x, 设S(△CDG)=y,则由DG∥BF,且BD:DC=2:1可知,S(△BCF)=9y,即S(BDGF)=8y, 同时,由于BD:DC=2:1,AE=ED,可知S(△ABE)=S(△BDE)=S(△ACD)=1/3*S=35平方厘米, 所以35+3x=8y, 4x+y=35, 所以可求得,x=7,y=7, 所以阴影部分面积为:S(△BDE)+S(△AEF)=35+7=42。麻烦采纳,谢谢!
overo0o 2022-04-01 23:06 优艾设计网_设计圈 30 由题, 把Rt△ABC折叠,使A、B两点重合,则∠A=∠EBA, 再沿BE折叠,C点恰好与D点重合,则∠EBA=∠CBE,即∠A=∠EBA=∠CBE,而在Rt△ABC中, ∠A+∠ABC=90°=3∠A,所以∠A=30°.
u_108645488 2022-04-01 23:11
刚好前端时间弄过个类似的,会VBA的话参考一下我下面的VBA代码,不会的话,直接下载附加我弄好的数据!
12345678910111213141516171819202122232425262728293031Option
Explicit
Dim
r()
As
Variant
, k
As
Long
Sub
main()
Dim
a(1
To
5)
As
Variant
, i
As
Long
, p
As
Long
a(1) =
"A"
: a(2) =
"B"
: a(3) =
"C"
: a(4) =
"D"
: a(5) =
"E"
Erase
r: k = 0
perm a(), 1, 5
ActiveSheet.Cells.Clear
For
i = 1
To优艾设计网_在线设计
k
p = p + 1
ActiveSheet.Range(
"a"
& p) = r(i)
Next
i
MsgBox p
End
Sub
Private
Sub
perm(
ByRef
arr()
As
Variant
,
ByVal
s
As
Long
,
ByVal
e
As
Long
)
Dim
i
As
Integer
, res
As
String
, tmp
As
Variant
If
s > e
Then
For
i = LBound(arr)
To
UBound(arr)
res = res & arr(i)
Next
i
k = k + 1
ReDim
Preserve
r(1
To
k)
r(k) = res
Else
For
i = s
To
e
tmp = arr(s): arr(s) = arr(i): arr(i) = tmp
perm arr(), s + 1, e
tmp = arr(s): arr(s) = arr(i): arr(i) = tmp
Next
i
End
If
End
Sub
很抱歉,回答者上传的附件已失效掩饰不了的爱 2022-04-01 23:19 分析:由已知根据等腰三角形的性质可得到几组相等的角,再根据三角形外角的性质可得到∠C与∠A之间的关系,从而再利用三角形内角和定理求解即可.解答:解:∵AE=ED,∴∠ADE=∠A,∴∠DEB=∠A+∠ADE=2∠A,∵BD=ED,∴∠ABD=∠DEB=2∠A,∴∠BDC优艾设计网_设计=∠A+∠ABD=3∠A,∵BD=BC,∴∠C=∠BDC=3∠A,∵AB=AC,∴∠ABC=∠C=3∠A,∵∠ABC+∠C+∠A=180°,∴7∠A=180°,∴∠A=( 180/7)°.
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