document.write( "Question 263596: A piece of wire 40cm long is to be cut into two pieces. One piece wil be bent to form a circle; the other will be bent to form a square. Find the lengths of the two pieces that cause the sum of the area of the circle and square to be a minimum. \n" ); document.write( "
Algebra.Com's Answer #194300 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! A piece of wire 40cm long is to be cut into two pieces. \n" ); document.write( " One piece will be bent to form a circle; the other will be bent to form a square. \n" ); document.write( " Find the lengths of the two pieces that cause the sum of the area of the circle and square to be a minimum. \n" ); document.write( ": \n" ); document.write( "Let x = circumference of the circle \n" ); document.write( "then \n" ); document.write( "(40-x) = perimeter of the square \n" ); document.write( ": \n" ); document.write( "Find the radius of the circle \n" ); document.write( "r = \n" ); document.write( "Find the area of the circle \n" ); document.write( "a = \n" ); document.write( "a = \n" ); document.write( "Cancel pi \n" ); document.write( "a = \n" ); document.write( ": \n" ); document.write( "Find the area of the square: \n" ); document.write( "a = \n" ); document.write( "a = \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "Total area \n" ); document.write( "A = \n" ); document.write( "Change to decimals, easier to combine like terms \n" ); document.write( "A = .07958x^2 + .0625x^2 - 5x + 100 \n" ); document.write( "A = .14208x^2 - 5x + 100 \n" ); document.write( ": \n" ); document.write( "Find the axis of symmetry [x = -b/(2a)] \n" ); document.write( "x = \n" ); document.write( "x = \n" ); document.write( "x ~ 17.6 inches, the piece of wire creating a circle \n" ); document.write( "and \n" ); document.write( "40 - 17.6 = 22.4 inches, the piece of wire creating the square \n" ); document.write( ": \n" ); document.write( "These lengths should give minimum area of the circle and square together \n" ); document.write( " |