cho tam giac MNK co MN = 3cm, MK = 5cm. Qua N dung duong thang cat doan thang Mk tai D sao cho góc MND = góc MKN
a) Chung minh tam giac MND đồng dạng tam giac MKN
b) tính MD, DK = ?
c) gọi MH la duong cao cua tam giac MNK, EM la duong cao cua tam giac MND. chung minh dien tich cua tam giac MNH = 4 lan dien tich tam giac MDE
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