document.write( "Question 1205671: By cutting away identical squares from each corner of a rectangular piece of cardboard and folding up the resulting flaps, an open box may be made (see the accompanying figure). If the cardboard is l = 16 in. long and w = 9 in. wide, find the dimensions of the resulting box if it is to have a total surface area of 128 in.2
\n" );
document.write( " \n" );
document.write( "
Algebra.Com's Answer #842630 by Theo(13342)![]() ![]() You can put this solution on YOUR website! the total surface of the rectangular piece of cardboard, before cutting, is equal to 16 * 9 = 144 square inches.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if you remove a square of x inches on a side from each corner of the box, the remaining surface area will be 16 * 9 - 4 * x^2 = 144 - 4 * x^2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if the remaining surface area is 128 square inches, then your formula becomes 144 - 4 * x^2 = 128.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "add 4 * x^2 to both sides and subtract 128 from both sides of the equation to get 144 - 128 = 4 * x^2 which simplifies to 16 = 4 * x^2 which simplifies further to 4 = x^2.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "solve for x to get x = 2.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the length will be 16 minus 2 * 2 = 12 \n" ); document.write( "the width will be 9 minus 2 * 2 = 5 \n" ); document.write( "the height will be 2.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the area of the bottom of the box will be 12 * 5 = 60 \n" ); document.write( "the area of the 2 vertical sides along the length will be 12 * 2 = 24 each for a total area of 48. \n" ); document.write( "the area of the 2 vertical sides along the width will be 5 * 2 = 10 each for a total area of 20.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the total surface area of the box will be 60 + 48 + 20 = 128 square inches.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |