document.write( "Question 1058852: two consecutive angles of a parallelogram are in the ratio 4:5. how many degrees are there in each angle of the parallelogram?
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Algebra.Com's Answer #673948 by Theo(13342) $\"\"$ $\"About$

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the sum of the consecutive angles of a parallelogram have to be equal to 180 degrees.
\n" ); document.write( "let x = one of the angles and let y = the other angle.
\n" ); document.write( "x + y = 180.
\n" ); document.write( "the ratio of one of these angles to the other is 4/5.
\n" ); document.write( "this means that x/y = 4/5
\n" ); document.write( "solve for x to get x = 4/5 * y.
\n" ); document.write( "x + y = 180 becomes 4/5 * y + y = 180 which becomes 9/5 * y = 180.
\n" ); document.write( "solve for y to get y = 180 * 5 / 9 which is equal to 100.
\n" ); document.write( "this makes 4/5 * y = 80.
\n" ); document.write( "the sum of the consecutive angles is equal to 100 + 80 which is equal to 180.
\n" ); document.write( "this confirms the solution is correct.
\n" ); document.write( "one of the angles of the parallelogram is 100 degrees and the other angle is 80 degrees.
\n" ); document.write( "opposite angles are equal so you get sum of the angles of the parallelogram is equal to 2 * 100 + 2 * 80 which is equal to 360.
\n" ); document.write( "the sum of the angles of an quadrilateral have to be equal to 360, so the solution is confirmed to be correct again. \n" ); document.write( "

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