cho tam giác ABC vuông cân tại A qua A vẽ đường thẳng d ở ngoài ABC. Vẽ BD\(\perp\) d, CE \(\perp\)d tại E, M là trung điểm BC. CMR:
a) BD +CE= DE
b) Tam giác MDE vuông cân
Cho tam giác ABC vuông cân ( AB=AC ). Qua A vẽ đường thẳng d ngoài tam giác ABC. Vẽ BD vuông góc với d tại D, CE vuông góc với d tại E. M là trung điểm BC. Chứng minh rằng:
a) BD+CE=DE
b) Tam giác MDE là tam giác vuông cân
Cho tam giác ABC vuông cân tại A. Qua A vẽ một đường thẳng d ở ngoài tam giác ABC. Vẽ BD vuông góc với d tại D,CE vuông góc với d tại E . M là trung điểm của BC. Cmr
A.BD+CE=DE
B.∆MDE vuông cân
Khó quá!Hu hu hu
1. Cho tam giác ABC vuông ở A có AB<AC. AH vuông góc với BC tại H, D là điểm trên cạnh BC sao cho AD=AB. Vẽ DE vuông góc với BC tại E. Chứng mih rằng AH=HE.
2. Cho tam giác ABC vuông cân tại A.. Qua A vẽ đường thẳng d ở ngoài tam giác ABC . Vẽ BD vuông góc với d taị D. CE vuông góc với d tại E. M là trung điểm CB. Chứng minh rằng:
a) BD + CE = DE
b) Tam giác MDE là tam giác vuông cân
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Cho tam giác ABC vuông tại A có AB = AC. Qua A kẻ đường thẳng d ở ngoài tam giác ABC. Vẽ BD và CE vuông góc với d. M là trung điểm BC. Chứng minh rằng:
a. BD + CE = DE?
b. Tam giác MDE vuông cân?
Cho tam giác ABC vuông cân tại A.. Qua A vẽ đường thẳng d ở ngoài tam giác ABC . Vẽ BD vuông góc với d taị D. CE vuông góc với d tại E. M là trung điểm CB. Chứng minh rằng:
a) BD + CE = DE
b) Tam giác MDE là tam giác vuông cân
giúp em với ạ, mai em cần rồi T-T
a) Ta có: \(\widehat{DAB}+\widehat{CAE}=180^0-\widehat{BAC}=90^0\)(1)
\(\widehat{DAB}+\widehat{DBA}=180^0-\widehat{BDA}=90^0\)(2)
Từ (1) và (2) \(\widehat{DAB}+\widehat{CAE}=\widehat{DAB}+\widehat{DBA}\Rightarrow\widehat{CAE}=\widehat{DBA}\)
Xét\(\Delta DAB\)và\(\Delta ECA\)có:\(\hept{\begin{cases}\widehat{BDA}=\widehat{AEC}=90^0\\AB=AC\\\widehat{DBA}=\widehat{CAE}\end{cases}\Rightarrow\Delta DAB=\Delta ECA}\)(cạnh huyền góc nhọn)
\(\Rightarrow\hept{\begin{cases}EC=AD\\BD=AE\end{cases}\Rightarrow BD+EC=AD+AE}=DE\)
Cho tam giác ABC vuông cân tại A. Qua A vẽ đường thẳng d sao cho B và C cùng thuộc một nửa mặt phẳng bờ d. Vẽ BD, CE cùng vuông góc với d (D, E thuộc D).
a) Chứng minh rằng DE = BD + CE.
b) Gọi M là trung điểm của BC. Chứng minh tam giác DME vuông cân tại M
tilado.edu.vn/student/facebook_view_question/code/747142 link đó bạn nào cần
Cho tam giác ABC vuông cân tại A, từ A kẻ đường thẳng d nằm ngoài tam giác ABC, kẻ BD vuông góc với d, CE cũng vuông góc với d; gọi M là TĐ của BC. CMR tam giác MDE vuông cân.
cho tam giác ABC vuông cân tại A qua A vẽ đường thẳng d sao cho B và C cùng thuộc nửa mặt phẳng bờ d vẽ BD vuông góc vs d tại D, CE vuông góc vs d tại E. CMR
a) DE=BD+CE, BD2+CE2=AB2
b)Gọi M là trung điểm cạnh DC. CMR tam giác DME là tam giác Vuông cân
cho tam giác ABC vuông cân tại A. Qua A vẽ đường thẳng d sao cho B và C cùng thuộc 1 nửa mặt phẳng bờ d. Vẽ BD vuông góc d tại D, CE vuông góc d tại E a) CM DE=BD+ CE, BD2+ CE2= AB B) Gouj M là trung điểm cạnh BC. CM tam giác DME là tam giác vuông cân
Tham khảo ở đây nha
https://olm.vn/hoi-dap/detail/12435070952.html
Tham khảo ở đây nha
Câu hỏi của Phạm Hương Giang - Toán lớp 7 - Học toán với OnlineMath