Algebra.Com's Answer #128694 by Edwin McCravy(20056)![\"\"](\"/images/stars/stars-13.gif\")  
You can put this solution on YOUR website!
Prove: the sum of the interior angles of a triangle is 180 degrees, can you please write a 2 column proof
\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Given: triangle ABC:\r\n" );
document.write( "\r\n" );
document.write( " \r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "To prove: ÐA + ÐB + ÐC = 180°\r\n" );
document.write( "\r\n" );
document.write( "Draw line through B parallel to AC Given a line and a pt. not on\r\n" );
document.write( "and label two points D and E, one the line, exactly one and only\r\n" );
document.write( "on each side of B one line can be drawn thru\r\n" );
document.write( " the point parallel to the line. \r\n" );
document.write( " \r\n" );
document.write( "\r\n" );
document.write( "ÐA = ÐABD Alternate interior angles formed by\r\n" );
document.write( " Transversal AB cutting parallel \r\n" );
document.write( " lines AC and DE must be equal.\r\n" );
document.write( "\r\n" );
document.write( "ÐC = ÐCBE alternate interior angles formed by\r\n" );
document.write( " Transversal CB cutting parallel \r\n" );
document.write( " lines AC and DE must be equal.\r\n" );
document.write( "\r\n" );
document.write( "ÐABD + ÐB + ÐCBE = 180° Their sum is a straight angle.\r\n" );
document.write( "\r\n" );
document.write( "ÐA + ÐB + ÐC = 180° Equals may be substituted for equals.\r\n" );
document.write( "\r\n" );
document.write( "Edwin \n" );
document.write( " |