Giup mink với nha !!Cho Tam giác ABC vuông cân tại A. H là trung điểm BC. M là trung điểm của B và H. Vẽ MD vuông góc với AB tại D, ME vuông góc với AC tại E . CMRa) AH vuông góc với BC b) AD =CE, BD=...

LN

Le ngoc phuong linh

31 tháng 12 2017 - olm

Giup mink với nha !!

Cho Tam giác ABC vuông cân tại A. H là trung điểm BC. M là trung điểm của B và H. Vẽ MD vuông góc với AB tại D, ME vuông góc với AC tại E . CMR

a) AH vuông góc với BC

b) AD =CE, BD= AE

c) MB²+ MC²= 2MA²

^{thanks trước nha !!}

#Toán lớp 7

0

NM

nguyễn mai bằng lòng

19 tháng 2 2018 - olm

cho tam giác abc vuông cân tại a. h là trung điểm cạnh bc. m là trung điểm cạnh bc. m là điểm nằm giữa b và h. vẽ md vuông góc ab tại d, me vuông góc với ac tại e. Cm:

a) ah vuông góc với bc

b) ad= ce, bd= ae

c) mb mũ 2 + mc mũ 2= 2ma mũ 2

#Toán lớp 7

0

HT

Hoàng Trang

20 tháng 7 2015 - olm

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

#Toán lớp 7

12

CL

Cao Linh Chi

13 tháng 2 2016

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CV

CUTE vô đối

7 tháng 3 2017

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HT

Hoàng Thị Ngọc Ánh

18 tháng 2 2022

Cho tam giác ABC vuông cân tại A, H là trung điểm của BC, M là điểm nằm giữa B và H. Vẽ MB vuông góc AB tại D, ME vuông góc AC tại E.Chứng minh:a) AH vuông góc với BCb) AD=CE; BD=AEc)MB^2+MC^2=2MA^2Mn giúp mik vs, lát 7h mik phải nộp bài rồi...

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#Toán lớp 7

0

MF

Mother fuck

26 tháng 12 2021

cho tam giác ABC vuông tại A (AB<AC). Gọi M là trung điểm của BC .Từ M vẽ MD vuông góc với AB ,ME vuông góc với ACa) chứng minh D là trung điểm của AB, tứ giác BDEMlà hình bình hànhb) vẽ AD vuông góc vs BC tại H . Gọi K là giao điểm của AH và DE. Đường thẳng DH cắt BK tại J và I là trung điểm của MK .chứng minh J là trọng tâm tam giác ABH và 3 điểm C,I.J thẳng...

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#Toán lớp 8

1

NH

Nguyễn Hoàng Minh

26 tháng 12 2021

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CN

CHÁU NGOAN BÁC HỒ

28 tháng 1 2020 - olm

Bài 1:Cho tam giác ABC cân có AB=AC=5cm, BC= 8cm.Kẻ AH vuông góc với BC ( H thuộc BC).a, Chứng minh HB=HCb, Tính độ dài AH.c, Kẻ HD vuông góc với AB(D thuộc AB), kẻ HE vuông góc với AC ( E thuộc AC).Chứng minh tam giác HDE cân.d, So sánh HD và HC.Bài 2:Cho tam giác ABC cân tại A có đường cao AH.a, Chứng minh tam giác ABH = tam giác ACH và AH là tia phân giác của góc BAC.b, Cho BH= 8cm, AB= 10cm.Tính AH.c,, Gọi E là trung điểm...

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Bài 1:
Cho tam giác ABC cân có AB=AC=5cm, BC= 8cm.Kẻ AH vuông góc với BC ( H thuộc BC).
a, Chứng minh HB=HC
b, Tính độ dài AH.
c, Kẻ HD vuông góc với AB(D thuộc AB), kẻ HE vuông góc với AC ( E thuộc AC).Chứng minh tam giác HDE cân.
d, So sánh HD và HC.
Bài 2:
Cho tam giác ABC cân tại A có đường cao AH.
a, Chứng minh tam giác ABH = tam giác ACH và AH là tia phân giác của góc BAC.
b, Cho BH= 8cm, AB= 10cm.Tính AH.
c,, Gọi E là trung điểm của AC và G là giao điểm của BE và AH.Tính HG.
d, Vẽ Hx song song với AC, Hx cắt AB tại F. Chứng minh C, G, F thẳng hàng.
Bài 3
Cho tam giác ABC có CA= CB= 10cm, AB= 12cm.kẻ CI vuông góc với AB.Kẻ IH vuông góc với AC, IK vuông góc với BC.
a, Chứng minh IB= IC và tính độ dài CI
b, Chứng minh IH= IK.
c, HK// AC.
Bài 4:
Cho tam giác ABC cân tại A, vẽ AH vuông góc với BC tại H.Biết AB= 10cm, BH= 6cm.
a, Tính AH
b, tam giác ABH= tam giác ACH.
c, trên BA lấy D, CA lấy E sao cho BD= CE.Chứng minh tam giác HDE cân.
d, AH là trung trực của DE.
Bài 5:
Cho tam giác ABC cân tại AGọi D là trung điểm của BC.Từ D kẻ DE vuông góc với AB, DF vuông góc với AC. Chứng minh rằng:
a, tam giác ABD= tam giác ACD.
b, AD vuông góc với BC.
c, Cho AC= 10cm, BC= 12cm.Tính AD.
d, tam giác DEF cân.
Bài 6:
Cho tam giác ABC cân tại A có góc A < 900. kẻ BH vuông góc với AC ,CK vuông góc với AC.Gọi O là giao điểm của BH và CK.
a, Chứng minh tam giác ABH=Tam giác ACH.
b, Tam giác OBC cân.
c, Tam giác OBK = tam giác OCK.
d, trên nửa mặt phẳng bờ BC không chứa điểm A lấy I sao cho IB=IC.Chứng minh 3 điểm A, O, I thẳng hàng.
Bài 7
Cho tam giác ABC cân tại A. Kẻ BD vuông góc với AC, CE vuông góc với AB. BD và CE cắt nhau tại H.
a, Tam giác ABD=tam giác ACE.
b, Tam giác BHC cân.
c, ED//BC
d, AH cắt BC tại K, trên HK lấy M sao cho K là trung điểm của HM.Chứng minh tam giác ACM vuông.
Bài 8
Cho tam giác ABC cân tại A. Kẻ BD vuông góc với AC, CE vuông góc với AB. BD và CE cắt nhau tại H.
a, BD= CE.
b, Tam giác BHC cân.
c, AH là trung trực của BC
d, Trên tia BD lấy K sao cho D là trung điểm của BK.So sánh góc ECB và góc DKC.
Bài9
Cho tam giác ABC cân tại A.vẽ trung tuyến AM .từ M kẻ ME vuông góc với AB tại E.kẻ MF vuông góc với AC tại F.
a, chứng minh tam giác BEM= tam giác CFM.
b, AM là trung trực vủa EF.
c, từ B kẻ đường thẳng vuông góc với AB tại B, từ C kẻ đường thẳng vuông góc với AC tại C, hai đường này cắt nhau tại D.Chứng minh A,M,D thẳng hàng.
Bài 10
Cho tam giác ABC cân tại AGọi M là trung điểm của AC.Trên tia đối MB lấy D sao cho DM= BM.
a, Chứng minh Tam giác BMC= tam giác DMA.Suy ra AD//BC.
b, tam giác ACD cân.
c. trên tia đối CA lấy E sao cho CA= CE.Chuwngsminh DC đi qua trung điểm I của BE.
Bài 11: Cho tam giác ABC cân tại A (AB = AC ), M là trung điểm của BC. Gọi D là điểm là điểm nằm giữa A và M. Chứng minh rằng:
a) AM là tia phân giác của góc A?
b) (ABD = (ACD.
c) (BCD là tam giác cân ?
Bài 12: Cho tam giác ABC vuông tại A , đường phân giác BD. Kẻ DE vuông góc với BC (E BC). Gọi F là giao điểm của BA và ED.

Giúp mk với các bạn đẹp trai xinh gái ai làm đúng mk tik cho

Sắp hết Tết rùi giúp mk vs

#Toán lớp 7

9

K

karma

26 tháng 4 2020

uôi dài v**

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NT

Nguyễn Thanh Tâm

26 tháng 4 2020

ủa r viết ngần đó thì mất bn tg thek

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TH

Thu Hà

24 tháng 3 2018 - olm

1.cho tam giác ABC , có góc B và góc C nhọn , M là trung điểm BC. Vẽ BD vương góc với AM tại D, CE vuông với AM tại E. CMR:
a. BD< BC/2
b. AD+AE<AB+AC
c. 2AM<AB+AC
2 . Cho tam giác ABC vuông tại A , vẽ AH vuông góc với BC tại H.CMR BC+AH>AB+AC

#Toán lớp 7

0