document.write( "Question 167656: In a certain triangle the measure of one angle is double the measure of a second angle, but is five degress less than the measure of the third angle. If the sum of the measures of the 3 interior angles is always 180 form an algebraic equation to express the problem?\r
\n" );
document.write( "\n" );
document.write( "I came up with a+2a-5=180, but this just doesn't seem right to me, could you please help? Thank you. \n" );
document.write( "
Algebra.Com's Answer #123560 by partygirl1122(6)![]() ![]() ![]() You can put this solution on YOUR website! let the angles of the triangle be k, m, and r. \n" ); document.write( "let k = 2*m \n" ); document.write( "let k = c-r \n" ); document.write( "----- \n" ); document.write( "if k = 2*m, then m = k/2 \n" ); document.write( "----- \n" ); document.write( "if k = r-5, then r = k+5 \n" ); document.write( "----- \n" ); document.write( "since the sum of the interior angles of a triangle = 180 degrees, then \n" ); document.write( "k + m + r = 180 \n" ); document.write( "substituting k/2 for m, and k+5 for r, we get: \n" ); document.write( "k + k/2 + k + 5 = 180 \n" ); document.write( "----- \n" ); document.write( "combining like terms, we get: \n" ); document.write( "2*k + k/2 + 5 = 180 \n" ); document.write( "subtracting 5 from both side of the equation we get: \n" ); document.write( "2*k + k/2 = 175 \n" ); document.write( "----- \n" ); document.write( "since 2*k is the same as 4*k/2, we can substitute to get: \n" ); document.write( "4*k/2 + k/2 = 175 \n" ); document.write( "since the denominators on the left hand side of the equation are the same, this equation becomes: \n" ); document.write( "(4*k + k)/2 = 175 \n" ); document.write( "which becomes: \n" ); document.write( "(5*k)/2 = 175 \n" ); document.write( "----- \n" ); document.write( "multiplying both sides of the equation by 2 gets: \n" ); document.write( "5*k = 350 \n" ); document.write( "dividing both sides of the equation by 5 gets: \n" ); document.write( "k = 70 \n" ); document.write( "----- \n" ); document.write( "k = 70 \n" ); document.write( "m = k/2 = 35 \n" ); document.write( "r = k+5 = 75 \n" ); document.write( "----- \n" ); document.write( "70 + 35 + 75 = 180 \n" ); document.write( "----- \n" ); document.write( "algebraic expression to solve the problem was derived above. \n" ); document.write( "it started off as \n" ); document.write( "k+m+r = 180 \n" ); document.write( "we solved for m in terms of k. \n" ); document.write( "we solved for r in terms of k. \n" ); document.write( "equation became: \n" ); document.write( "k + (k/2) + (k+5) = 180 \n" ); document.write( "----- \n" ); document.write( "the rest was simplification to come up with k = 70. \n" ); document.write( "----- \n" ); document.write( " |