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nt871113
2 năm trước
Cho hình thang ABCD ( AB // CD ) với AB = a ; CD = b. Gọi I là giao điểm của hai đường chéo . Đường thẳng qua I và song song với AB cắt hai cạnh bên tại E và F. Chứng minh rằng : EF=2ab/a+b GIÚP VỚI MÌNH ĐANG CẦN GẤPPPPPP
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1/ tỉ số phần trăm của 45 và 200 là 2/ lớp 5a có 40 học sinh , trong đó có 24 học sinh nữ còn lại là học sinh nam . Như vậy tỉ số phần trăm giữa học sinh nam và học sinh cả lớp là 3/lớp 5a có 32 bạn học sinh , trong đó có 14 bạn nữ . tỉ số phần trăm của số học sinh nữ và số học sinh cả lớp là 4/ một trường tiểu học có 532 học sinh nam . Số học sinh nữ ít hơn số học sinh nam là 114 em . tỉ số phần trăm của số học sinh nữ và số học sinh toàn trường là 5/ khối 5 có 310 em học sinh nam . Số học sinh nữ nhiều hơn số học sinh nam là 155 em . Tỉ số phần trăm phần trăm của số học học sinh nữ và số học sinh khối 5 là 6/ một người bỏ ra 2872000 đồng tiền vốn để mua hoa . Sau khi bán hết số hoa mhuoiwf đó thu được 3590000 đồng. Như vậy người đó đã lãi được số phần trăm tiền vốn là ai làm được tất cả đúng mình vote 5 sao cảm ơn và cho câu trả lời hay nhất nha nhớ ai làm hết mà đúng mới được đó nha

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