document.write( "Question 1037714: If c=14x° & A=(3x+10)° what is the value of x in the isosceles trapezoid? \n" ); document.write( "
Algebra.Com's Answer #652511 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
An isosceles trapezoid looks like this:
\n" ); document.write( " , with two congruent \"green%28acute%29\" angles and two congruent \"red%28obtuse%29\" angles.
\n" ); document.write( "The \"green%28acute%29\" angles are supplementary to the \"red%28obtuse%29\" angles.
\n" ); document.write( "The vertices in a trapezoid (or any polygon) are named going around in order (clockwise or counterclockwise).
\n" ); document.write( "No matter how the vertices in your isosceles trapezoid are named,
\n" ); document.write( "\"A\" and \"C\"angles are opposite vertices/angles.
\n" ); document.write( "The opposite angles in an isosceles trapezoid
\n" ); document.write( "(one acute and one obtuse) are supplementary,
\n" ); document.write( "meaning that their measures add up to \"180%5Eo\" , so
\n" ); document.write( "\"A%2BC=180%5E0\" , meaning that \"14x%2B%283x%2B10%29=180\" .
\n" ); document.write( "Now, all you have to do is solve that equation:
\n" ); document.write( "\"14x%2B%283x%2B10%29=180\"
\n" ); document.write( "\"%2814x%2B3x%29%2B10=180\"
\n" ); document.write( "\"17x%2B10=180\"
\n" ); document.write( "\"17x=180-10\"
\n" ); document.write( "\"17x=170\"
\n" ); document.write( "\"x=170%2F17\"
\n" ); document.write( "\"highlight%28x=10%29\"
\n" ); document.write( "If we are curious, we can figure out the measures of the angles as
\n" ); document.write( "\"C=14x%5Eo=14%2A%2810%5Eo%29=140%5Eo\" and
\n" ); document.write( "\"A=%283x%2B10%29%5Eo=%283%2A10%2B10%29%5Eo=%2830%2B10%29%5Eo=40%5Eo\" .
\n" ); document.write( "So, the isosceles trapezoid in the problem looks like this:
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "NOTE:
\n" ); document.write( "A rectangle is considered a special case of a trapezoid,
\n" ); document.write( "and it can be considered an isosceles trapezoid.
\n" ); document.write( "In that case, all four angles would measure \"90%5Eo\" ,
\n" ); document.write( "with no acute or obtuse angle,
\n" ); document.write( "but opposite angles would still be supplementary.
\n" ); document.write( "That is not the case with the problem above,
\n" ); document.write( "but the reasoning above would have worked just the same,
\n" ); document.write( "even if we had figured out that both angles were right angles.
\n" ); document.write( "
\n" );