Cho tam giac ABC co BC=5cm . Diem D thuoc canh BC sao cho DC=2cm . Cho biet goc ADB=70o
a)Tinh do dai BD?
b)Tren nua mat phang chua A co bo BC , ve tia Dx sao cho goc CDx =50o.Tinh goc ADx?
c)Goi M la giao diem cua tia Dx va canh AC ,tim cac tam giac trong hinh ve