document.write( "Question 339653: Prove: If an isosceles triangle has an altitude from the vertex to the base, then the altitude bisects the vertex angle.
\n" ); document.write( "Given: Triangle ABC is isosceles; Line segment CD is the altitude to the base segment AB
\n" ); document.write( "To Prove: Line segment CD bisects angle ACB\r
\n" ); document.write( "\n" ); document.write( "I really need some help with this.I have to write out a 2 column proof and a plan for the proof.I kinda have a proof but not sure if its right?
\n" ); document.write( "And I have no idea how to do a plan for the proof??? I don't remember learning that? PLEASE HELP me with the proof and the plan. \n" ); document.write( "

Algebra.Com's Answer #243356 by Edwin McCravy(20056) $\"\"$ $\"About$

You can put this solution on YOUR website!

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document.write( "Plan:\r\n" );
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document.write( "The measures of AC and BC are equal because they are legs of isosceles triangle ABC.\r\n" );
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document.write( "Angles ADC and BDC are right angles because CD is an altitude, which is\r\n" );
document.write( "perpendicular to the base.\r\n" );
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document.write( "The measure of CD is equal to itself.\r\n" );
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document.write( "Right triangles ADC and BDC are congruent because two right triangles are\r\n" );
document.write( "congruent if the measures of the hypotenuse and a leg of one right triangle\r\n" );
document.write( "are equal to the measures of the corresponding parts of the other right\r\n" );
document.write( "triangle.\r\n" );
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document.write( "Angle ACD and Angle BCD have equal measures because they are corresponding\r\n" );
document.write( "parts of congruent right triangles ADC and BDC.\r\n" );
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document.write( "CD bisects angle ACB because it divides the angle ACB into two angles with\r\n" );
document.write( "equal measures, ACD and BCD. \r\n" );
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document.write( "Now you can write the two-column proof.\r\n" );
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document.write( "Edwin

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