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document.write( "The plot for this problem is shown in the Figure on the right.\r\n" );
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document.write( "We need to prove that two red colored segments are congruent.\r\n" );
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document.write( "Let us draw the perpendicular CF (green line) from the point C to the line DE.\r\n" );
document.write( "The perpendicular CF is parallel to both lines AD and BE.\r\n" );
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document.write( "Thus we have three parallel lines AD, CF and BE, and two transverses DE and AB.\r\n" );
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document.write( "Now apply this property:\r\n" );
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document.write( " If three parallel lines cut off two congruent segments in one transverse line, \r\n" );
document.write( " then they cut off two congruent segments in any other transverse line.\r\n" );
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document.write( "(See the lesson \r\n" );
document.write( "Three parallel lines cutting off congruent segments in a transverse line \r\n" );
document.write( "in this site).\r\n" );
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document.write( " Figure\r\n" );
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