document.write( "Question 186035: Question: Given an isosceles triangle with a smaller base 0f 2, a perimeter of 70, and acute base angles of 60 degrees, find the trapezoid's area.\r
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\n" ); document.write( "b1 is 2 but I don't know if I draw altitudes for the trapezoid, the altitudes will equal 2 because the altitudes will make a square. I'm not sure on that part.
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Algebra.Com's Answer #139556 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
Given an isosceles trapezoid with a smaller base 0f 2, a perimeter of 70, and acute base angles of 60 degrees, find the trapezoid's area.
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document.write( "Let the slanted sides of the trapezoid be X:\r\n" );
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document.write( "Draw in these two altitudes of the trapezoid, and\r\n" );
document.write( "let their lengths be H:\r\n" );
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document.write( "Now we look at only the right triangle on the \r\n" );
document.write( "left, letting its bottom side's length be Z\r\n" );
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document.write( "Now we know that \r\n" );
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document.write( "\"H%2FX=sin%2860%29\" and \"Z%2FX=cos%2860%29\"\r\n" );
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document.write( "or\r\n" );
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document.write( "\"H=X%2Asin%2860%29\" and \"Z=X%2Acos%2860%29\" \r\n" );
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document.write( "We also know that \"cos%2860%29=1%2F2\" and \"sin%2860%29=sqrt%283%29%2F2\"\r\n" );
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document.write( "so\r\n" );
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document.write( "\"Z+=+X%2A%281%2F2%29\"  and \"H=X%2A%28sqrt%283%29%2F2%29\"\r\n" );
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document.write( "or\r\n" );
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document.write( "\"Z+=+X%2F2\"  and \"H=%28X%2Asqrt%283%29%2F2%29\"\r\n" );
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document.write( "so we replace \"Z\" by \"X%2F2\" and H by \"%28X%2Asqrt%283%29%29%2F2\"\r\n" );
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document.write( "Now we go back to the trapezoid:\r\n" );
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document.write( "We know the small segment on the bottom is 2 because\r\n" );
document.write( "the top side of the trapezoid is 2.  And we know that\r\n" );
document.write( "the right segment on the bottom is also \"X%2F2\" because\r\n" );
document.write( "the right triangle on the left and the one on the right \r\n" );
document.write( "are congruent.\r\n" );
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document.write( "Now we are told that the perimeter is 70.\r\n" );
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document.write( "So to form the perimeter, we add up all four sides of the \r\n" );
document.write( "trapezoid.\r\n" );
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document.write( "The left side of the trapezoid is \"X\"\r\n" );
document.write( "The bottom side is this sum \"X%2F2%2B2%2BX%2F2\"\r\n" );
document.write( "The right side is \"X\"\r\n" );
document.write( "The top side is \"2\".\r\n" );
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document.write( "So the sum of all those must equal 70:\r\n" );
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document.write( "\"X%2B%28X%2F2%2B2%2BX%2F2%29%2BX%2B2=70\"\r\n" );
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document.write( "We solve that for X and get 22\r\n" );
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document.write( "So now we know that the bottom side is\r\n" );
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document.write( "\"X%2F2%2B2%2BX%2F2+=+X%2B2+=+22%2B2+=+24\" \r\n" );
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document.write( "and that is the larger base of the trapezoid.\r\n" );
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document.write( "And its height is \"%28X%2Asqrt%283%29%29%2F2=%2824sqrt%283%29%29%2F2=12sqrt%283%29\".\r\n" );
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document.write( "Now we can find the area using \"B%5B1%5D=2\", \"B%5B2%5D=24\", and\r\n" );
document.write( "\"H=12sqrt%283%29\", in the formula\r\n" );
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document.write( "\"Area=%28B%5B1%5D%2BB%5B2%5D%29%28H%2F2%29\"\r\n" );
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document.write( "\"Area=%282%2B24%29%2812sqrt%283%29%2F2%29=26%286sqrt%283%29%29=+156sqrt%283%29=270.199926\".\r\n" );
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document.write( "Edwin
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