Cho tam giác ABC có AB<AC<BC. Vẽ phân giác AD, đường cao CH. Chứng minh CH>AD
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Trên cạnh AD lấy điểm E sao cho AE=AB .
Xét \(\Delta ABC\)và \(\Delta AEC\)có :
\(AB=AE\)(GT)
\(\widehat{A}_1=\widehat{A}_2\)(vì AC là tia phân giác góc BAD )
\(AC:\)Cạnh chung
Do đó : tam giác ABC = tam giác AEC (c-g-c)
\(\Rightarrow BC=CE\)( cặp cạnh tương ứng ) (1)
\(\widehat{B}_1=\widehat{E}_1\)( cặp góc tương ứng )
Vì tứ giác ABCD có :
\(\widehat{A}+\widehat{B}+\widehat{C}+\widehat{C}=360^o\)( tính chất tứ giác lồi )
Mà \(\widehat{A}+\widehat{C}=180^o\)( GT)
\(\Rightarrow\widehat{B}+\widehat{D}=180^o\)
Mà \(\widehat{B}_1=\widehat{E}_1\)
\(\widehat{E}_2+\widehat{E}_1=180^o\)
\(\Rightarrow\widehat{E}_2=\widehat{D}\)
\(\Rightarrow\Delta CDE\)cân tại C .
\(\Rightarrow DC=CE\)(2)
Từ (1) và (2)
\(\hept{\begin{cases}BC=CE\\DC=CE\end{cases}}\)
\(\Rightarrow DC=BC\left(dpcm\right)\)
https://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.htmlhttps://olm.vn/hoi-dap/detail/239868952049.html
bài 2:
ta có: AB<AC<BC(Vì 3cm<4cm<5cm)
=> góc C>góc A> góc B (Các cạnh và góc đồi diện trong tam giác)
Bài 3:
*Xét tam giác ABC, có:
góc A+góc B+góc c= 180 độ( tổng 3 góc 1 tam giác)
hay góc A+60 độ +40 độ=180độ
=> góc A= 180 độ-60 độ-40 độ.
=> góc A=80 độ
Ta có: góc A>góc B>góc C(vì 80 độ>60 độ>40 độ)
=> BC>AC>AB( Các cạnh và góc đối diện trong tam giác)
bài 2:
ta có: AB <AC <BC (Vì 3cm <4cm <5cm)
=> góc C>góc A> góc B (Các cạnh và góc đồi diện trong tam giác)
Bài 3:
*Xét tam giác ABC, có:
góc A+góc B+góc c= 180 độ( tổng 3 góc 1 tam giác)
hay góc A+60 độ +40 độ=180độ
=> góc A= 180 độ-60 độ-40 độ.
=> góc A=80 độ
Ta có: góc A>góc B>góc C(vì 80 độ>60 độ>40 độ)
=> BC>AC>AB( Các cạnh và góc đối diện trong tam giác)
HT mik làm giống bạn Dương Mạnh Quyết
Bài 1:
a: Xét ΔABC có \(AC^2=AB^2+BC^2\)
nên ΔABC vuông tại B
b: XétΔABC có BC<AB<AC
nên \(\widehat{A}< \widehat{C}< \widehat{B}\)