Cho tam giac ABC co goc B, goc C< 90. ve ra phia ngoai tam giac ay cac tam giac vuong can abd va ace(goc ABD=ACE=90)

ke DI va EK vuong goc vs BC

CMR: 1, BI=CK

2,BC=DI+EK

cho tam giac abc vuong o a. ve ve phia ngoai tam giac abc cac tam giac deu abd va ace. goi i la giao diem cua be va cd. c/m ia la p/g cua goc die

Cho tam giac ABC nhon .Ve ve phia ngoai tam giac ABC cac tam giac deu ABD va ACE . Goi M la giao diem cua DC va BE.Chung minh rang.

a, Tam giac ABE bang tam giac ADC.

b, Tinh goc BMC.

Cho tam giac ABC  co cac goc nho hon 120 do .ve o phia ngoai  tam giac ABC cac tam giac deu ABD ,ACE .goi M la giao diem cua DC va BE.cm :

a)goc BMC bang 120 do ,b)goc AMB bang 120 do

cho tam giac ABC vuong tai A, ve ra phia ngoai tam giac do cac tam giac ABD vuong can o B, ACF vuong can o C goi H la giao diem cua AB va CD, K la giao diem của AC va BF.

a) CM AH = AK

b)CM AH² = BH*CK

cho tam giac abc co cac goc nho hon 120 do ve o phia ngoai tam giac abc cac tam giac deu abd ace goi m la giao diem dc va be

cho tam giác ABC có gocB a góc C <90 . ve ra phia ngoai tam giac acam giac uong can ABD a ACE(rong o goc ABD a goc ACEdeu bang 90 do)e DI va CKcung vuong goc voi cach BC cmr

a)BI=CK;E=HC

b)BC=DI+EK

cho tam giac ABC o phia ngoai tam giac ve cac tam giac vuong can tai A la tam giac ABD , tam giac ACE ve hinh binh hanh ADIE chung minh

a, AI=BC

b, AI vuong goc voi BC

Cho tam giac ABC ko co goc nao >=120⁰ o phia ngoai tam giac ABC ve cac tam giac deu ABD va ACE

a)CM: DC=BE

b)I la giao diem cua DC va BE. Tinh so do goc BIC