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phat22126
2 năm trước
Hệ thống phao hàng hải ,giúp cho tàu,thuyền trên biển,sông ,hồ ,…biết khu vực nào an toàn,khu vực nào nguy hiểm,…Đường thủy nội bộ còn có phao phân luồng.. Để xác định khoảng cách giữa hai phao tiêu A và B (Hình vẽ) bất kỳ trên một dòng sông ,người ta sử dụng một cọc tiêu C (Sao cho C,A,B thẳng hàng ) ,đặt giác kế tại vị trí D (Sao cho CD vuông góc với CB),ngắm phao A ,xác định góc ,sau đó ngắm phao B ,xác định góc . Hãy xác định khoảng cách giữa hai phao A và B (Làm tròn đến mét) ,biết CD = 20m ,các góc và Giả sử mặt sông im và phẳng .
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