document.write( "Question 176017: The base of a triangle is 8cm greater than the height. The area is 42cm^2. Find the height and length of the base. How do I set up this problem to get the answer? \n" ); document.write( "
Algebra.Com's Answer #131134 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Let b=base and h=height\r
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\n" ); document.write( "\n" ); document.write( "\"The base of a triangle is 8cm greater than the height\" means that \"b=h%2B8\"\r
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\n" ); document.write( "\n" ); document.write( "\"A=%281%2F2%29bh\" Start with the area of a triangle formula\r
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\n" ); document.write( "\n" ); document.write( "\"42=%281%2F2%29%28h%2B8%29h\" Plug in \"A=42\" (the given area) and \"b=h%2B8\"\r
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\n" ); document.write( "\n" ); document.write( "\"42%2A2=%28h%2B8%29h\" Multiply both sides by 2.\r
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\n" ); document.write( "\n" ); document.write( "\"84=%28h%2B8%29h\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"84=h%28h%2B8%29\" Rearrange the terms.\r
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\n" ); document.write( "\n" ); document.write( "\"84=h%5E2%2B8h\" Distribute\r
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\n" ); document.write( "\n" ); document.write( "\"0=h%5E2%2B8h-84\" Subtract 84 from both sides.\r
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\n" ); document.write( "\n" ); document.write( "Notice we have a quadratic equation in the form of \"ah%5E2%2Bbh%2Bc\" where \"a=1\", \"b=8\", and \"c=-84\"\r
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\n" ); document.write( "\n" ); document.write( "Let's use the quadratic formula to solve for h\r
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\n" ); document.write( "\n" ); document.write( "\"h+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29\" Start with the quadratic formula\r
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\n" ); document.write( "\n" ); document.write( "\"h+=+%28-%288%29+%2B-+sqrt%28+%288%29%5E2-4%281%29%28-84%29+%29%29%2F%282%281%29%29\" Plug in \"a=1\", \"b=8\", and \"c=-84\"\r
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\n" ); document.write( "\n" ); document.write( "\"h+=+%28-8+%2B-+sqrt%28+64-4%281%29%28-84%29+%29%29%2F%282%281%29%29\" Square \"8\" to get \"64\". \r
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\n" ); document.write( "\n" ); document.write( "\"h+=+%28-8+%2B-+sqrt%28+64--336+%29%29%2F%282%281%29%29\" Multiply \"4%281%29%28-84%29\" to get \"-336\"\r
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\n" ); document.write( "\n" ); document.write( "\"h+=+%28-8+%2B-+sqrt%28+64%2B336+%29%29%2F%282%281%29%29\" Rewrite \"sqrt%2864--336%29\" as \"sqrt%2864%2B336%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"h+=+%28-8+%2B-+sqrt%28+400+%29%29%2F%282%281%29%29\" Add \"64\" to \"336\" to get \"400\"\r
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\n" ); document.write( "\n" ); document.write( "\"h+=+%28-8+%2B-+sqrt%28+400+%29%29%2F%282%29\" Multiply \"2\" and \"1\" to get \"2\". \r
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\n" ); document.write( "\n" ); document.write( "\"h+=+%28-8+%2B-+20%29%2F%282%29\" Take the square root of \"400\" to get \"20\". \r
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\n" ); document.write( "\n" ); document.write( "\"h+=+%28-8+%2B+20%29%2F%282%29\" or \"h+=+%28-8+-+20%29%2F%282%29\" Break up the expression. \r
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\n" ); document.write( "\n" ); document.write( "\"h+=+%2812%29%2F%282%29\" or \"h+=++%28-28%29%2F%282%29\" Combine like terms. \r
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\n" ); document.write( "\n" ); document.write( "\"h+=+6\" or \"h+=+-14\" Simplify. \r
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\n" ); document.write( "\n" ); document.write( "So the possible answers are \"h+=+6\" or \"h+=+-14\" \r
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\n" ); document.write( "\n" ); document.write( "However, since a negative height is not possible, this means that \"h+=+-14\" is NOT a solution\r
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\n" ); document.write( "\n" ); document.write( "So the only answer for the height is \"h+=+6\" which means that the height is 6 cm.\r
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\n" ); document.write( "\n" ); document.write( "\"b=h%2B8\" Go back to the first equation\r
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\n" ); document.write( "\n" ); document.write( "\"b=6%2B8\" Plug in \"h=6\"\r
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\n" ); document.write( "\n" ); document.write( "\"b=14\" Add. So the base is 14 cm.\r
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\n" ); document.write( "\n" ); document.write( "Answer:\r
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\n" ); document.write( "\n" ); document.write( "So the base is 14 cm and the height is 6 cm
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