Chứng minh tam giác ACD cân

Cho tam giac ABC can tai A . Ve tia phan giac cua goc A cat BC tai H . Chung minh tam giac ABH = tam giac ACH. Tren tia doi cua tia AB lay dem D sao cho AB=AD ,chung minh tam giac ACD can . Chung minh AH song song CD. (Cac ban ve inh giup minh nha).