document.write( "Question 1208983: A triangle with sides of 21 cm, 72 cm and 75 cm is cut into parts that form a quadrilateral. Find, in cm2, the area of the largest quadrilateral that can be formed.
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Algebra.Com's Answer #847532 by ikleyn(52781)\"\" \"About 
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\n" ); document.write( "A triangle with sides of 21 cm, 72 cm and 75 cm is cut into parts that form a quadrilateral.
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document.write( "In this problem, it is assumed that the quadrilateral is formed of disjoint parts\r\n" );
document.write( "of the triangle with no holes (empty spaces) and without overlaying.\r\n" );
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document.write( "Then the area of the quadrilateral is equal to the area of the original triangle.\r\n" );
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document.write( "The area of the original triangle can be found using the Heron's formula\r\n" );
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document.write( "    S = \"sqrt%28s%2A%28s-21%29%2A%28s-72%29%2A%28s-75%29%29\",  where s is the semi-perimeter  s = \"%2821%2B72%2B75%29%2F2\" = 84 cm.\r\n" );
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document.write( "So, for the area we have\r\n" );
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document.write( "    S = \"sqrt%2884%2A%2884-21%29%2A%2884-72%29%2A%2884-75%29%29\" = \"sqrt%2884%2A63%2A12%2A9%29\" = 756 cm^2.    ANSWER\r\n" );
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\n" ); document.write( "\n" ); document.write( "By the way, it is easy to check that the triangle with the sides\r
\n" ); document.write( "\n" ); document.write( "21 cm, 72 cm and 75 cm is a right-angled triangle.\r
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\n" ); document.write( "\n" ); document.write( "So, it gives another, more simple way to calculate its area \"%281%2F2%29%2A21%2A72\" = 756 cm^2.\r
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