document.write( "Question 58470: an airplane over the pacific sights an atoll at a 5 degree angle of depression. If the plane is 450 meters above water, how many kilometers is it from a point 450 meters above the atoll. \n" ); document.write( "
Algebra.Com's Answer #40052 by Edwin McCravy(20060)\"\" \"About 
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an airplane over the pacific sights an atoll at a 5ｰ\r\n" );
document.write( "angle of depression. If the plane is 450 meters above \r\n" );
document.write( "water, how many kilometers is it from a point 450 \r\n" );
document.write( "meters above the atoll.\r\n" );
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document.write( "                 x\r\n" );
document.write( "P覧覧覧覧覧覧覧覧覧覧覧覧覧覧覧猷\r\n" );
document.write( "        .   5ｰ                  |\r\n" );
document.write( "                .               |450 m\r\n" );
document.write( "                        .       |\r\n" );
document.write( "                                . \r\n" );
document.write( "                                A\r\n" );
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document.write( "Let the plane be at point P, the atoll at point A,\r\n" );
document.write( "and let Q be the point 450 m above the atoll at A.\r\n" );
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document.write( "We want to find the distance PQ, which we will call x.\r\n" );
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document.write( "QA = 450, and it is the side opposite the 5ｰ angle in \r\n" );
document.write( "right triangle PQA.\r\n" );
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document.write( "PO = x = the side adjacent the 5ｰ angle in right\r\n" );
document.write( "triangle PQA.\r\n" );
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document.write( "So since we are given the opposite side, and we want\r\n" );
document.write( "to find the adjacent side, we use the only one of the\r\n" );
document.write( "basic three trigonometric functions that involves the \r\n" );
document.write( "opposite and the adjacent, which is the tangent. So\r\n" );
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document.write( "          opp \r\n" );
document.write( "tan 5ｰ = -----\r\n" );
document.write( "          adj\r\n" );
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document.write( "          450 \r\n" );
document.write( "tan 5ｰ = -----\r\n" );
document.write( "           x\r\n" );
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document.write( "Multiply both sides by x:\r\n" );
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document.write( "x tan 5ｰ = 450\r\n" );
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document.write( "Divide both sides by tan 5ｰ:\r\n" );
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document.write( "             450\r\n" );
document.write( "       x = --------\r\n" );
document.write( "            tan 5ｰ\r\n" );
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document.write( "Use a calculator\r\n" );
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document.write( "                 450\r\n" );
document.write( "       x = --------------\r\n" );
document.write( "             .0874886635\r\n" );
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document.write( "       x = 5142.523535\r\n" );
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document.write( "Since 450 is rounded probably to the\r\n" );
document.write( "nearest 10 feet, we probably should round\r\n" );
document.write( "the final answer likewise, to 5140 feet.\r\n" );
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document.write( "Edwin
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