document.write( "Question 1041173: the hypotenuse of a right triangle is 12 inches and the area is 24 square inches. Find the dimension of the triangle, correct to one decimal place. \n" ); document.write( "
Algebra.Com's Answer #656125 by ikleyn(52788)\"\" \"About 
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\n" ); document.write( "The hypotenuse of a right triangle is 12 inches and the area is 24 square inches.
\n" ); document.write( "Find the dimension of the triangle, correct to one decimal place.
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document.write( "\"x%5E2+%2B+y%5E2\" = \"12%5E2\",       (1)\r\n" );
document.write( "\"%281%2F2%29%2Axy\"  = \"24\",       (2)\r\n" );
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document.write( "or\r\n" );
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document.write( "\"x%5E2+%2B+y%5E2\" = \"144\",        (1')\r\n" );
document.write( "\"xy\"     = \"48\".         (2')\r\n" );
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document.write( "Multiply eqn. (2') by 2 and add to eqn(1') (both sides). You will get\r\n" );
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document.write( "\"x%5E2+%2B+2xy+%2B+y%5E2\" = \"144+%2B+2%2A48\",   or\r\n" );
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document.write( "\"%28x%2By%29%5E2\" = \"240\",   or\r\n" );
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document.write( "\"x%2B+y\" = \"sqrt%28240%29\" = \"4%2Asqrt%2815%29\".\r\n" );
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document.write( "Thus from (1) and (2) we got \r\n" );
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document.write( "x + y = \"4%2Asqrt%2815%29\",         (3)\r\n" );
document.write( "xy    = 48.             (4)\r\n" );
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document.write( "   Notice that in this way we decreased the degree of the original equations/system.\r\n" );
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document.write( "   It makes it easier to work in future with (3),(4) instead of (1),(2).\r\n" );
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document.write( "Next, from (3)  x = \"4%2Asqrt%2815%29+-+y\". Substitute it into (4) and get\r\n" );
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document.write( "\"%284%2Asqrt%2815%29-y%29%2Ay\" = \"48\".     (5)\r\n" );
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document.write( "\"y%5E2+-+%284%2Asqrt%2815%29%29%2Ay+%2B+48\" = \"0\",\r\n" );
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document.write( "Solve this quadratic equation by applying the quadratic formula. You will get\r\n" );
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document.write( "\"y%5B1%2C2%5D\" = \"%284%2Asqrt%2815%29+%2B-+sqrt%28240-4%2A48%29%29%2F2\" = \"%284%2Asqrt%2815%29+%2B-+sqrt%2848%29%29%2F2\" = \"2%2Asqrt%2815%29+%2B-+2%2Asqrt%283%29\".\r\n" );
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document.write( "Then \"x%5B1%2C2%5D\" = \"4%2Asqrt%285%29\" - \"%282%2Asqrt%2815%29+%2B-+2%2Asqrt%283%29%29\".\r\n" );
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document.write( "Answer. There are two solutions:\r\n" );
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document.write( "        a)  x = \"2%2Asqrt%2815%29-2%2Asqrt%283%29\",  y = \"2%2Asqrt%2815%29+%2B+2%2Asqrt%283%29\",  and\r\n" );
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document.write( "        b)  x = \"2%2Asqrt%2815%29%2B2%2Asqrt%283%29\",  y = \"2%2Asqrt%2815%29+-+2%2Asqrt%283%29\".\r\n" );
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document.write( "Check.  a) \"x%5E2+%2By%5E2\" = \"4%2A15+%2B+4%2A3+%2B+4%2A15+%2B+4%2A3\" = 144,  xy = 4*15 - 4*3 = 60 - 12 = 48.   OK ! ! !\r\n" );
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