document.write( "Question 750169: A 30 cm piece of wire is cut into two pieces. One piece is bent into the shape of a square the other piece is bent into the shape of a rectangle with length to width ratio of 2:1 What are the length's of the two pieces if the sum of the areas of the square and rectangle is a minimum?\r
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document.write( "Can you please help me out? Thanks so much in advance:)
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document.write( "Can you also show the steps it would really help me understand better:) \n" );
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Algebra.Com's Answer #456465 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! A 30 cm piece of wire is cut into two pieces. \n" ); document.write( " One piece is bent into the shape of a square. the other piece is bent into \n" ); document.write( " the shape of a rectangle with length to width ratio of 2:1 \n" ); document.write( " What are the length's of the two pieces if the sum of the areas of the square \n" ); document.write( " and rectangle is a minimum? \n" ); document.write( ": \n" ); document.write( "let x = length of the side of square \n" ); document.write( "let y = length of the width of the rectangle \n" ); document.write( "then \n" ); document.write( "2y = Length of rectangle \n" ); document.write( "So we have \n" ); document.write( "4x + 2(2y) + 2(y) = 30 \n" ); document.write( "4x + 6y = 30 \n" ); document.write( "6y = 30 - 4x \n" ); document.write( "simplify, divide by 2 \n" ); document.write( "3y = 15 - 2x \n" ); document.write( "Divide by 3 \n" ); document.write( "y = (5- \n" ); document.write( "the total area equation \n" ); document.write( "A = x^2 + (2y*y) \n" ); document.write( "A = x^2 + 2y^2 \n" ); document.write( "replace y with (5- \n" ); document.write( "A = x^2 + 2(5-.67x)^2 \n" ); document.write( "FOIL (5-.67x)(5-.67x) \n" ); document.write( "A = x^2 + 2(25-6.7x+.44x^2) \n" ); document.write( "A = x^2 + 50 - 13.14x + .88x^2 \n" ); document.write( "A = 1.88x^2 - 13.14x + 50 \n" ); document.write( "Find the minimum by finding the axis of symmetry using x = -b/(2a) \n" ); document.write( "x = \n" ); document.write( "x = \n" ); document.write( "x = 3.5 cm is the side of the square for minimum area, therefore \n" ); document.write( "4(3.5) = 14 cm is piece made into a square \n" ); document.write( "Find the piece made into the rectangle \n" ); document.write( "y = 5 - .67(3.5) \n" ); document.write( "y = 2.66 cm is the width of the rectangle, therefore \n" ); document.write( "6(2.66) ~ 16 cm is the piece made into the rectangle \n" ); document.write( ": \n" ); document.write( ":\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |