cho tam giac ABC co goc C=40o. Tren canh AB lay diem M, tren nua mat phang bo AB co chua diem C ve tia Mx sao cho goc AMx=goc B
a) chung minh rang: Mx // BC
b) goi D la giao diem cua Mx va AC. lay N nam giua C va D. Tren nua mat phang bo AC ko chua B ve tia Ny sao cho goc CNy=goc C. chung minh rang: Mx // Ny
c) tinh so do goc MDC
giup mik vs T-T
cho tam giac abc co ab be hon ac goi m la giao diem cua bc tren tia doi cua tia ma lay diem d sao cho ma = md so sanh goc bam va goc cam
Cho tam giac abc co ab<ac goi m la trung diem cua bc tren tia am lay diem d sao cho n la trung diem cua ad
Cm: tam giac abm= tam giac dcmCm ab//dc va so sanh goc mab va goc macTren doan thang am lay g sao cho ag=2gm tai bg cat ac tai n tia cg cat ab tai p.Cm am+bn+cp>3/4(ab+ac+bc)cho tam giac ABC co goc B = 45 độ goc C bang 30 do duong cao AH M la diem tren AC sao cho AM = AH a, chung minh M la trung diem cua AC,
b, tinh so do goc AMB :
c, goi D la giao diem cua BM va phan giac goc ACB thi tam giac ABD la tam giac gi
cho tam giac abc vuong tai a,co ab=3cm,ac=4cm.
a)tinh bc va so sanhcac goc cua tam giac abc
b)ke ah vuong goc voi bc,lay d tren bc sao cho h la trung diem cua bd.cm:tam giac abd can tai a
c)tren ah lay m sao cho h la trung diem cua am.cm:tam giac abm la tam giac can
cho tam giac abc co goc a = 90 do tren canh bc lay diem e sao cho be = ba tia phan gic cua goc b cat ac tai m
a) chung minh tam giac abm = tam giac ebm
b) so sanh am va em
c) tinh so do goc bem
giup minh voi
cho tam giac ABC vuong tai C(AC>CB).
a,biet goc A co so do bang 40 do.Tinh so do goc B
b,tren tia doi cua tia CB lay diem D sao cho CD=CB.Chung minh tam giac ABC=tam giac ADC
c,tren AD lay diem M,tren AB lay diem N sao cho AM=AN.Chung minh CM=CN
cho tam giac ABC co goc A nhở hơn 90 do tren mat phang bo AB co chua diem B ve AE VUONG AC va AE =AC goi M la trung diem cua doan MA diem H sao cho MA =MH chung minh tam giac ABE = TAM GIAC ADC chung minh BH=CA chung minh GOC BAH = GOC ADE
cho tam giac ABC, co goc A=90 do. Tia BD cua goc B . Tren canh BC lay diem E sao cho BE=BA.
a) So sanh AD=DE ; goc EDC va goc ABC
b) C/m AE vuong goc BD