1 cho tam giac abc can a , goc a bang 40 do lay d khac phia b so voi ac thoa man goc cad bang 60 do goc cad bang 80 do chung minh bd vuong goc voi ac

2 cho tam giac abc vuong can a . d la diem bat ki tren ab. tren nua mat phang bo ab tu c ve tia bx sao cho goc abx bang 135 do. duong thang  vuong goc voi dc ve tu d cat bx o e . chung minh tam giac dec vuong can

3 cho tam giac abc can b goc abc bang 80 do , i la diem trong tam giac sao cho goc iac bang 10 do, ica bang 30 do tinh goc abi

4 cho tam giac abc can a co goc a bang 100 do , bc =a, ac =b ve phia ngoai tam giac abc ve tam giac abd can d co goc adb bang 140 do tinh ch vi tam giac adb theo a,b

ve hinh gium minh voi , xin mn day

1. cho tam giac ABC can tai A, ve diem M, Nbat ki tren duong trung truc ca doan thang BC.CM:

a,tam giac MBCcan tai M

b, MNC=MNB

2.cho tam giac ABC cao M la trung diem cua canh BC. qua B ke duong thang Bx \\ AC, qua C ke Cy \\ AB. giao diem cua Cy, Bx la D. CM: A, D, M thang hang.

3. do dai 2 canh goc vuong cua mot tam giac vuong ti le voi 7 va 24. chu vi tam giac bang 112. tinh do dai canh huyen.

4.cho tam giac ABC can tai A, canh day nho hon canh ben. duong trung truc cua AC cat BC tai M. tren tia doi cua AM lay N \ AN = BM.

a, CM: 2 goc AMC va BAC bang nhau

b, CM: CM = CN

c, de CM vuong voi CN hi tam giac ABC phai co them dieu kien gi?

5. cho tam giac ABC deu. tren tia doi cua tia phan giac goc BAC lay D \ AD = AB. tinh cac goc cua tam giac DBC.