document.write( "Question 106084: Floor plans for a building have the four corners of a room located at the points (2,3), (11,6), (-3,18), and (8,21). Determine whether the side through the points (2,3) and (11,6) is perpendicular to the side through the points (2,3) and (-3,18). \n" ); document.write( "
Algebra.Com's Answer #77188 by MathLover1(20850)\"\" \"About 
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1. the side through the points (\"2\",\"3\") and (\"11\",\"6\")\r
\n" ); document.write( "\n" ); document.write( "Find a slope \"a%5B1%5D\":\r
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\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D\" = (\"y%5B2%5D\"\"y%5B1%5D\")/(\"x%5B2%5D\"\"x%5B1%5D\")\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D+=+%286-3%29%2F%2811-2%29\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=+3%2F9\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D+=+1%2F3\"\r
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\n" ); document.write( "\n" ); document.write( "2.
\n" ); document.write( "the side through the points (\"2\",\"3\") and (\"-3\",\"18\")\r
\n" ); document.write( "\n" ); document.write( "Find a slope \"a%5B2%5D\":\r
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\n" ); document.write( "\n" ); document.write( "\"a%5B2%5D\" = (\"y%5B2%5D\"\"y%5B1%5D\")/(\"x%5B2%5D\"\"x%5B1%5D\")\r
\n" ); document.write( "\n" ); document.write( "\"a%5B2%5D+=+%2818-3%29%2F%28-3-2%29\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B2%5D=+15%2F%28-5%29\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B2%5D+=+-3\"\r
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\n" ); document.write( "\n" ); document.write( "If the product of slopes is equal to \"-1\", lines are \"perpendicular\".\r
\n" ); document.write( "\n" ); document.write( "We have \"a%5B1%5D+=1%2F3\" and \"a%5B2%5D+=+-3\",\r
\n" ); document.write( "\n" ); document.write( "so\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D%2Aa%5B2%5D+=+%281%2F3%29%2A%28-3%29\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D%2Aa%5B2%5D+=+-1\" ............. => your lines are \"perpendicular\"
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