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hoaiphuong2608
2 năm trước
Người ta đào một cái giếng hình trụ có bán kính 60cm và có độ sâu là 10m. a) Hãy tính thể tích của cái giếng (kết quả làm tròn đến chữ số thập phân thứ nhất). b) Đất, khi được lấy lên thì thể tích của nó nở thêm 20% nữa. Đất đào lên được chuyển đến vị trí khác bằng các xe tải có thể chở được mỗi chuyến 3m^2 đất. Hỏi phải cần bao nhiêu chuyến xe tải như thế? (Chú ý: Cho biết pi = 3,14. Thể tích của hình trụ bằng diện tích đáy nhân với chiều cao). Hộ em bài này vớiiiiiii Chi tiết dễ hiểu ạ!!!
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