give isosceles trapezoid abcd ( ab // cd,ab<cd) from a draw ah perpendicular ab , ah intersects bd at h . from b draw bk perpendicular ab , bk intersects ac at k a) what figure is quadrilateral ahkb?why? b) Given that E,F are the midpoints of AB, DC; I and G are respectively the intersection points of AC with BD , CH with DK . Prove that four points E,I,G,F are collincar
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given isosceles trapezoid ABCD (AB//CD), AC is perpendicular to BD and the length of the height of the ABCD is 7 cm. What is the area of the isosceles trapezoid ABCD?
Let ABCD be a trapezoid with AB // CD, Â = D = 90o and AB = AD = CD/2.
Find the measure of the angle BCD.
-Giải bằng TA hay TV vậy bạn?
-Gọi E là trung điểm DC.
\(\Rightarrow AB=DE=\dfrac{1}{2}CD\).
-Tứ giác ABED có: \(AB=DE\), AB//DE.
\(\Rightarrow\)ABED là hình bình hành mà \(\widehat{ADE}=90^0\).
\(\Rightarrow\)ABED là hình chữ nhật mà \(AD=AB\).
\(\Rightarrow\)ABED là hình vuông \(\Rightarrow\widehat{DBE}=45^0,\widehat{BED}=90^0\).
-△BCD có BE vừa là trung tuyến vừa là đường cao.
\(\Rightarrow\)BCD cân tại E \(\Rightarrow\)BE là tia phân giác của \(\widehat{BCD}\).
\(\Rightarrow\widehat{BCD}=2\widehat{DBE}=2.45^0=90^0\)
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trapezoid ABCD with AB // CD , AB < CD , AD = BC = AB , the angle BDC = 30 degrees . calculate the angles A, B ,C ? help me 
Given a trapezoid ABCD with base AB=4cm , CD=6cm , and góc C + góc D = 90 độ . Let M, N be respectively the midpoints of the segments AB and CD . Evaluate MN.
Answer: MN= ? cm
chỗ tiếng việt chỗ tiếng anh là sao
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As shown in the figure, ABCD is trapezoid (AB//CD), \(AM=\dfrac{1}{2}MD,BN=\dfrac{1}{2}NC\). Then x = ...
kẻ AC cắt MN tại I
ta có \(\dfrac{AM}{MD}=\dfrac{BN}{NC}\left(=\dfrac{1}{2}\right)\Rightarrow\)MN//DC//AB(định lí Talet đảo)
ta có:
\(\dfrac{AM}{MD}=\dfrac{1}{2}\Rightarrow\dfrac{AM}{AD}=\dfrac{AM}{AM+MD}=\dfrac{1}{1+2}=\dfrac{1}{3}\\ \Rightarrow\dfrac{BN}{BC}=\dfrac{1}{3}\Rightarrow\dfrac{NC}{BC}=\dfrac{2}{3}\)
tam giác ADC có MI//DC nên :\(\dfrac{MI}{DC}=\dfrac{AM}{AD}\Rightarrow\dfrac{MI}{\left(x+2\right)\left(x-2\right)}=\dfrac{1}{3}\Rightarrow\left(x+2\right)\left(x-2\right)=3MI\)
tam giac CAB có IN//AB nên:
\(\dfrac{NI}{AB}=\dfrac{BN}{BC}\Rightarrow\dfrac{NI}{x+4}=\dfrac{2}{3}\Rightarrow2\left(x+4\right)=3NI\)
\(\left(x+2\right)\left(x-2\right)+2\left(x+4\right)=3MI+3NI\\ \Leftrightarrow x^2-4+2x+8=3\left(MI+NI\right)=3MN=39\\ \Leftrightarrow x^2+2x+4-39=0\\ \Leftrightarrow x^2+2x-35=0\\ \Leftrightarrow\left(x-5\right)\left(x+7\right)=0\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-7\end{matrix}\right.\)
Vậy x=5 hoặc x=-7
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Let ABCD be a trapezoid with bases AB, CD and O be the intersection of AC and BD. If the areas of triangle OAB, triangle OCD are 16cm2, 40cm2respectively and M is the midpoint of BD, then the area of the triangle AMD is .........cm2.
Let ABCD be a trapezoid with bases AB, CD and O be the intersection of AC and BD. If the areas of triangle OAB, triangle OCD are 16cm2, 40cm2respectively and M is the midpoint of BD, then the area of the triangle AMD is .........cm2.
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Let ABCD be a trapezoid with bases AB, CD and O be the intersection of AC and BD. If the areas of triangle OAB, triangle OCD are 16cm2, 40cm2respectively and M is the midpoint of BD, then the area of the triangle AMD is .........cm2.
đựng đường cao 2 bên áp dụng 2 tam giác đồng dạng suy ra tỉ số diện tích
đáp án 22 cm2
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Given a trapezoid ABCD with base , and . Let M, N be respectively the midpoints of the segments . Evaluate MN.
Answer: cm
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Given a trapezoid ABCD with base ,
and
. Let M, N be respectively the midpoints of the segments
. Evaluate MN.
Answer: cm
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