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Caocoanh
2 năm trước
cho hình vuông có chu vi = 120 cm . một hình thang vuông có diện tích bằng diện tích hình vuông đó. a)tính diện tích hinh thang vuông . b)kéo dài đáy nhỏ của hình thang để được 1 hình chữ nhật . tính tỉ số phần trăm tắng thêm và tỉ số phần trăm ban đầu (biết tổng độ dìa 2 cạnh đáy là 45cm , và tỉ số 2 cạnh đáy đó là 4/5
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