document.write( "Question 1105669: How do you find the radius of a circle inscribed into a scalene triangle \n" ); document.write( "

Algebra.Com's Answer #720537 by ikleyn(52786) $\"\"$ $\"About$

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document.write( "The radius of a  circle inscribed in a scalene triangle is equal to the area of the triangle divided by semi-perimeter:\r\n" );
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document.write( "r = ,     (1)\r\n" );
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document.write( "where A is the area and \"s\" is the semi-perimeter.\r\n" );
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document.write( "Or, equivalently, A = r*s.\r\n" );
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document.write( "For the proof, see the lesson\r\n" );
document.write( "    - Proof of the formula for the area of a triangle via the radius of the inscribed circle \r\n" );
document.write( "in this site.\r\n" );
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document.write( "So, if you know the side lengths of your scalene triangle, you can calculate its area using the Heron's formula, and then use the formula (1).\r\n" );
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document.write( "On Heron's formula, see the lessons\r\n" );
document.write( "    - Proof of the Heron's formula for the area of a triangle \r\n" );
document.write( "    - One more proof of the Heron's formula for the area of a triangle \r\n" );
document.write( "in this site.\r\n" );
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