document.write( "Question 242218: The area of the rectangular piece of cardboard shown on the left is 198 square inches. The cardboard is used to make an open box by cutting a 2 inch square from each corner and turning up the sides. If the box is to have a volume of 196 cubic inches, find the length and width of the cardboard that must be used. \n" ); document.write( "
Algebra.Com's Answer #177348 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! The area of the rectangular piece of cardboard shown on the left is 198 square inches. \n" ); document.write( "The cardboard is used to make an open box by cutting a 2 inch square from each corner and turning up the sides. \n" ); document.write( " If the box is to have a volume of 196 cubic inches, find the length and width of the cardboard that must be used. \n" ); document.write( ": \n" ); document.write( "Area of the original piece of cardboard \n" ); document.write( "L * W = 198 sq/in \n" ); document.write( "L = \n" ); document.write( ": \n" ); document.write( "Volume L*W*H = 196 cu/in \n" ); document.write( "(removing 2\" squares reduces the length and width by 4\", height = 2\" \n" ); document.write( "(L-4)*(W-4)*2 = 196 \n" ); document.write( "Simplify, divide both sides by 2 \n" ); document.write( "(L-4)*(W-4) = 98 \n" ); document.write( "FOIL \n" ); document.write( "LW - 4L - 4W + 16 = 98 \n" ); document.write( ": \n" ); document.write( "LW - 4L - 4W + 16 - 98 = 0 \n" ); document.write( ": \n" ); document.write( "LW - 4L - 4W - 82 = 0 \n" ); document.write( ": \n" ); document.write( "From the area equation, replace L with 198/W \n" ); document.write( " \n" ); document.write( "Cancel W, mult by 4 \n" ); document.write( "198 - \n" ); document.write( ": \n" ); document.write( "Mult by W to get rid of the denominator \n" ); document.write( "198W - 792 - 4W^2 - 82W \n" ); document.write( ": \n" ); document.write( "Arrange as a quadratic equation \n" ); document.write( "-4W^2 + 198W - 82W - 792 = 0 \n" ); document.write( ": \n" ); document.write( "-4W^2 + 116W - 792 = 0 \n" ); document.write( "Divide by -2, simplify and change the signs \n" ); document.write( "2W^2 - 58W + 396 = 0 \n" ); document.write( "This will factor \n" ); document.write( "(2W - 22)(W - 18}) = 0 \n" ); document.write( "Two solutions \n" ); document.write( "2W = 22 \n" ); document.write( "W = 11 \n" ); document.write( "and \n" ); document.write( "W = 18 \n" ); document.write( "; \n" ); document.write( "18\" by 11\" is the cardboard used \n" ); document.write( ": \n" ); document.write( "Check the area: 18 * 11 = 198 \n" ); document.write( ": \n" ); document.write( "Check the vol of the box \n" ); document.write( "(18-4)*(11-4)* 2 = 196\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |