document.write( "Question 939075: A piece of wire 40cm long is to be cut into two pieces. One piece will 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 #572335 by ankor@dixie-net.com(22740)\"\" \"About 
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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( "We know that the circumference of the circle + the perimeter of the square = 40
\n" ); document.write( "Let x = the circumference of the circle
\n" ); document.write( "Find r in terms of x
\n" ); document.write( "\"2%2Api%2Ar+=+x\"
\n" ); document.write( "r = \"x%2F%282%2Api%29\"
\n" ); document.write( "\"Area+=+pi%2Ar%5E2\",
\n" ); document.write( "therefore
\n" ); document.write( "A = \"pi%2A%28x%2F%282%2Api%29%29%5E2\" = \"pi%2A%28x%5E2%2F%284%2Api%5E2%29%29\" = \"x%5E2%2F%284%2Api%29\" is the area of the circle
\n" ); document.write( ":
\n" ); document.write( "(40-x) = the perimeter of the square
\n" ); document.write( "then
\n" ); document.write( "\"%28%2840-x%29%29%2F4\" = one side of the square
\n" ); document.write( "and
\n" ); document.write( "\"%28%28%2840-x%29%29%2F4%29%5E2\" = the area of the square
\n" ); document.write( ":
\n" ); document.write( "Total Area
\n" ); document.write( "A(x) = \"x%5E2%2F%284%2Api%29\" + \"%28%28%2840-x%29%29%2F4%29%5E2\"
\n" ); document.write( "Graph this equation
\n" ); document.write( "
\n" ); document.write( "Put this equation into my graphing calc, min occurs when x = 17.6 cm is the piece to make the circle
\n" ); document.write( "therefore the piece of wire to make the square is 40 - 17.6 = 22.4 cm
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\n" ); document.write( "Did this make sense to you? let me know; ankor@att.net
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