CHO TAM GIÁC ABC CÂN TẠI A. VẼ AH VUÔNG GÓC BC . HD VUÔNG GÓC AB TẠI D, HE VUÔNG GÓC AC TẠI E. CHỨNG MINH
A, BH=CH
B,BD=CE
cho tam giác ABC cân tại A . Vẽ AH xuông góc với BC tại H . Vẽ HD vuông góc với AB tại D , HE vuông góc với AC tại E . chứng minh rằng
a) BH = HC
b) BD = CE
a: Xét ΔAHB vuông tại H và ΔAHC vuông tại H có
AB=AC
AH chung
=>ΔAHB=ΔAHC
=>HB=HC
b: Xét ΔHDB vuông tại D và ΔHEC vuông tại E có
HB=HC
góc B=góc C
=>ΔHDB=ΔHEC
=>BD=CE
cho tam giác ABC cân tại A vẽ AH vuông góc BC tại H . Vẽ HD vuông góc vớ AB tại D , HE vuông góc với AC tại E. chứng minh Bd = CE
mà thằng hiếu nhá,ko nick nào tao kb với mày đâu
ho tam giác ABC vuông tại A, AH vuông góc với BC. a) Cho BH = 4cm, CH = 2cm. Tính AB, AC. b) Vẽ HD vuông góc với AB tại D, HE vuông góc với AC tại E. Chứng minh BD = BC.cos^3B; DE^3 = BD . CE. BC
Cho tam giác ABC cân tại A, vẽ AH vuông góc với BC tại H, vẽ HD vuông góc với AB tại D, HE vuông góc với AC tại E. CMR :
a, AH = HC
b, BD = CE
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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Bài 5 : Cho tam giác ABC vuông tại A có đường cao AH , kẻ HE vuông góc AB tại E và HD vuông góc AC tại D. Chứng minh
a) AE . AB = AD.AC
b) AH.(tanB + tanC ) = BC
a: Xét ΔAHB vuông tại H có HE là đường cao
nên \(AE\cdot AB=AH^2\left(1\right)\)
Xét ΔAHC vuông tại H có HD là đường cao
nên \(AD\cdot AC=AH^2\left(2\right)\)
Từ (1) và (2) suy ra \(AE\cdot AB=AD\cdot AC\)
Cho tam giác ABC vuông tại A, đường cao AH. HD, HE vuông góc AB, AC tại D, E. Chứng minh:
BD√CH + CE√BH = AH√BC
cho tam giác abc vuông tại A(AB<AC) vẽ AH vuông góc BC(H thuộc BC) D là điểm trên cạnh AC sao cho AD = AB Vẽ DE vuông góc với BC (E thuộc BC) DK vuông góc với AH tại K Chứng minh
a, AH = DK
b, Tam giác AHE vuông cân