document.write( "Question 218034: Dalton has a closed rectangular box with a square base at least 10 inches long have a surface area of 900 square inches. what dimensions will give the box a maximum volume? \n" ); document.write( "
Algebra.Com's Answer #164363 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! Dalton has a closed rectangular box with a square base at least 10 inches long \n" ); document.write( " have a surface area of 900 square inches. \n" ); document.write( " what dimensions will give the box a maximum volume? \n" ); document.write( "; \n" ); document.write( "Let x = the side of the square base \n" ); document.write( "Actually the maximum is when the box is a perfect cube, therefore \n" ); document.write( "let x = the height of the box also \n" ); document.write( ": \n" ); document.write( "Surface area equation, find h: \n" ); document.write( "6x^2 = 900 \n" ); document.write( "simplify divide by 6 \n" ); document.write( "x^2 = 150 \n" ); document.write( "x = \n" ); document.write( "x = 12.247\" \n" ); document.write( ": \n" ); document.write( "Max vol: 12.247 by 12.247 by 12.247, and 12.247^3 = 1836.9 cu/in \n" ); document.write( ": \n" ); document.write( "You can prove this: \n" ); document.write( "let the height = h, \n" ); document.write( ": \n" ); document.write( "Surface area equation, find h: \n" ); document.write( "2x^2 + 4xh = 900 \n" ); document.write( "simplify divide by 2 \n" ); document.write( "x^2 + 2xh = 450 \n" ); document.write( "2xh = -x^2 + 450 \n" ); document.write( "h = \n" ); document.write( ": \n" ); document.write( "Volume equation \n" ); document.write( "V = x^2 * h \n" ); document.write( "Replace h \n" ); document.write( "V = x^2( \n" ); document.write( "V = x( \n" ); document.write( "V = x( \n" ); document.write( " \n" ); document.write( "Graph this equation y=V \n" ); document.write( " \n" ); document.write( ": \n" ); document.write( "Shows max volume when x is a little over 12\"; vol is about 1800 cu/in\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |