document.write( "Question 758127: twice the first angle is 20 deg less than the third, 1/2 of the third is 60 deg less than the sum of the 1st and 2nd angles.find the angles \n" ); document.write( "
Algebra.Com's Answer #461428 by ankor@dixie-net.com(22740)\"\" \"About 
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Three angles, A,B,C;
\n" ); document.write( "Just write an equation for what it says.
\n" ); document.write( ":
\n" ); document.write( "twice the first angle is 20 deg less than the third,
\n" ); document.write( "2A = C-20
\n" ); document.write( "or
\n" ); document.write( "C = 2A+20
\n" ); document.write( ":
\n" ); document.write( "1/2 of the third is 60 deg less than the sum of the 1st and 2nd angles.
\n" ); document.write( ".5C = A + B - 60
\n" ); document.write( "multiply both sides by 2
\n" ); document.write( "C = 2A + 2B - 120
\n" ); document.write( "therefore
\n" ); document.write( "2A+20 = A + B - 60
\n" ); document.write( "2A - A = B - 60 - 20
\n" ); document.write( "A = B-80
\n" ); document.write( "or
\n" ); document.write( "B = A+80
\n" ); document.write( ":
\n" ); document.write( "And assuming this is a triangle
\n" ); document.write( "A + B + C = 180
\n" ); document.write( "replace B with (A+80); replace C with (2A+20)
\n" ); document.write( "A + A+80) + 2a+20 = 180
\n" ); document.write( "4A + 100 = 180
\n" ); document.write( "4A = 180 - 100
\n" ); document.write( "4A = 80
\n" ); document.write( "Divide both sides by 4
\n" ); document.write( "A = 20 degrees
\n" ); document.write( "then
\n" ); document.write( "B = 20 + 80
\n" ); document.write( "B = 100 degrees
\n" ); document.write( "and
\n" ); document.write( "C = 2(20)+20
\n" ); document.write( "C = 60 degrees
\n" ); document.write( ":
\n" ); document.write( "20 + 100 + 60 = 180; confirms our solutions
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