ta co goc b = goc c (vi tam giac abc can tai a )= goc 180 do - goc a / 2 =180 do - 90 do /2=45 do.
ta co goc b = goc c (vi tam giac abc can tai a )= goc 180 do - goc a / 2 =180 do - 90 do /2=45 do.
cho tam giac ABC can tai A va tam giac DEF can tai D biet goc A bang 80 do goc E bang 50 do thi
cho tam giac ABC vuong tai A ,co AC=2AB.lay D la trung diem cua AC .dung AH,CK vuong goc voii BC.
a) cm; goc ABC = goc CDK va tam giac AHB = tam giac CKD
b) cm : DA= DC =DH va KH = KC
c) goi I la trung diem cua BD . Cm: tam giac AHI = tam giac KHI tu do tinh soo do goc IHK
d ) duong thang di qua A song song voi BC cat DK tai M. cm : H , I , M thang hang
e) duong thang AI cat BC tai N . cm : NK =
Cho tam giac ABC = tam giac DEF. Biet goc A + goc B = 130 do, goc E = 55 do. Tinh cac goc cua moi tam giac.
Cho tam giac abc can tai a.ve ah vuong goc voi bc tai h.cho ah=8 cm,bh=6 cm
a,tinh ab,ac
b,chung minh tam giac abh=tam giac ach
Cho tam giac ABC vuong tai A va M la trung diem AB ke MN vuong goc BC tai N Tren tia doi tia AB lay D sao cho AD=BN Ke ME vuong goc CD tai E Cac doan thang DN va ME cat nhau tai K Goi I la trung diem cua doan thang DK Tinh so do goc CIM
cho tam giac ABC vuong tai C góc B=40 do tia phan giac goc A cat BC tai D tren canh AB lay diem E sao cho EA=AC chứng minh tam giac ADE là tam giac vuong
tam giac abc có b-c=90.cac duong phan giac trong va ngoai cua goc a cat bc o dva e .chung minh rang tam giac ade vuong can
Cho tam giac ABC, biet B=50do, C=30 do
Tinh cac goc ngoai tai dinh A,B,C; Ve hinh minh hoa
giup mink☹
Cho tam giac ABC co AB=AC tia phan giac cua goc A cat BC tai M .Chung minh
tam giac ABC=TAM GIAC ACM
M la trung diem cua BC
AM vuong goc voi BC