bài 1 Cho tam giác ABC vuông tại A. AB=30 cm AC=40cm đường cao AH.Tia phân giác của góc B cắt AC tại D.TínhAH;HB;AD;DC 2cho hình thang ABCD (AB//CD) 2 đường chéo vuông góc.BD=15cm đường cao bằng 12 cm. Tính Sabcd

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