document.write( "Question 400735: Given: ADEC is an Isosceles Trapezoid
\n" ); document.write( "Prove: ABC is an Isosceles Triangle \n" ); document.write( "
Algebra.Com's Answer #283681 by Edwin McCravy(20056)\"\" \"About 
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document.write( "Draw DF and EG ⊥ AC\r\n" );
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document.write( "DF ⊥ AC            (drawn that way)\r\n" );
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document.write( "EG ⊥ AC            (drawn that way)\r\n" );
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document.write( "DF ∥ EG             lines perpendicular to the same line are parallel\r\n" );
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document.write( "DE ∥ FG             bases of a trapezoid are parallel \r\n" );
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document.write( "FDEG is a parallelogram   (both pairs of opposite sides parallel)\r\n" );
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document.write( "DF ≅ EG             Opposite sides of a parallelogram   \r\n" );
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document.write( "DA ≅ EC             legs of isosceles trapezoid\r\n" );
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document.write( "ᐃADF and ᐃCEG are right triangles  (DF and EG ∥ AC)\r\n" );
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document.write( "ᐃADF ≅ ᐃCEG        hypotenuse-leg theorem\r\n" );
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document.write( "∠A ≅ ∠C         corresponding parts of congruent triangles ADF and CEG\r\n" );
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document.write( "ᐃABC is isosceles   base angles congruent.   \r\n" );
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document.write( "Edwin
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