Question

Bai 1 cho goc XOY<90 do,lay A,B thuc Ox(A nam giua O va B)lay C,D thuoc Oy sao cho OA=OC,AB=CD

1)Tam giac OBD can

2)So sanh AD ba BC

3)Goi I la giao diem AD va BC tam gia IBDva tam giacIAC la cac tam giac gi

4)Chung minh tamgiaOAC=tam giacOCI

Bai 2 Cho tam giac ABC can tai A lay diem D thuo AB.tren tia doi cua tia CA lay CE=BD,DE cat BC o M

Chung minh M la trung diem DE

Bai 4Cho tam giac ABC nhon co goc A=60 do,hai duong phan giac BD va CF cat nhau tai I

1)Tinh goc BIC

2)IF la duong phan giac cua tam giac IBC

3)Chung minh+)tam giac BID=tam giac BIF

+)tam giac CID=tam giac CIF

Answer 1

ai biet lam bai nay thi giup minh nhanh len nhe minh dang can gap