https://olm.vn/hoi-dap/question/41860.html
bn vào đây tham khảo nha
https://olm.vn/hoi-dap/question/41860.html
bn vào đây tham khảo nha
Cho tam giac ABC do AB=AC. Goi M la trung diem cua canhBC
a) Chung minh tam giac ABM=tam giac ACM va AM vuong goc BC
b) Goi D la trung diem cua canh AC. Tren tia BD lay diem E sao cho DB=DE Chung minh tam giac BDA=tam giac EDC vaAB//CE
c) Tren tia doi cua MA lay diem F sao cho M la trung diem AF
e) Chung minh :E, C, F thang hang
cho goc xoy goi oz la tia phan giac cua goc xoy.trên tia ox lay M, trên tia oy lấy điểm N sao cho OM=ON.lay diem y bat ki tren tai Ox:
doan thang AB cat tia diem P .chung minh P la trung diem cua doan thang MN
cho tam giac ABC goi I la trung diem cua BC tren tia doi cua IA lay diem D sao cho IA=D
A) chung minh tam giac IAC bang tam giac IBC
cho tam giac ABC . goi mn lan luot la trung diem cua AB va AC. Chung minh MN//BC va MN=1/2 BC
cho tam giac ABC gọi D là trung diem cua AB tren tia doi cua tia DC lay diem M sao cho DM = Dc goi E la trung diem cua AC tren tia doi cua tia EM lay diem N sao cho EN = EM
a) chung minh AM = AN
b) MAN thang hang
c) A la trung diem cua MN
1. cho tam giac ABC. tren tia doi cua tia BA lay diem D sao cho BD=BA. tren canh BC lay diem E sao cho BE=\(\dfrac{1}{3}\)BC. goi K la giao diem cua AE va CD. Chung minh rang DK=KC
2. cho tam giac ABC can tai A co AB=AC=5cm,BC=3cm. ke trung tuyen AM
a. Chung minh rang AM vuong goc BC
b. tinh do dai AM
1cho hai tam giac vuong la abc va def co a=d=90 ,ac=df. hay bo sung them 1 dieu kien (ve canh hay ve goc ) de tam giac abc=tam giac def
2 cho tam giac abc can tai a (a<90) . ve bh vuong goc voi ac ( h thuoc ac) , ck vuong goc voi ab ( k thuoc ab)
a) chung minh ah=ak
b) goi i la giao diem cua bh va ck . chung minh rang ai la tia phan giac
3 tim cac cap tam giac bang nhau co tren hinh 131 sach vene 7
1.cho tam giac ABC. tren tia doi cua tia BA lay diem D sao cho BD=BA. tren canh BC lay diem E sao cho BE =1/3 BC. goi K la giao diem cua AE va CD. chung minh rang DK=KC
2. cho tam giac ABC can tai A co AB =AC =5cm, BC=3cm. ke trung tuyen AM
a) chung minh AM vuong goc BC
b) tinh do dai AM
cho tam giac ABC co so do cua BAC=100,ABC=50.GOI M la trung diem cua AB ,N LA TRUNG DIEM CUA AC.tren tia doi cua tia NM LAY DIEM E sao choNM=NE
a)tinh so do goc ACB
b)chunh minh tam giac ANM=CNE
c)chung minh BC=2MN
LAM CAU c) thoi nha