document.write( "Question 80865: Hi, I'd greatly appreciate help with this word problem: The length of a rectangle is 4 cm more than 2 times its width. If the area of the rectangle is 90 cm^2, find the dimensions of the rectangle to the nearest thousandth. \n" ); document.write( "
Algebra.Com's Answer #58012 by praseenakos@yahoo.com(507)![]() ![]() You can put this solution on YOUR website! QUESTION:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The length of a rectangle is 4 cm more than 2 times its width. If the area of the rectangle is 90 cm^2, find the dimensions of the rectangle to the nearest thousandth.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "ANSWER:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Assume that width of the rectangle is 'x' cm.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Then two times width = 2x\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "4 cm more than 2 times its width = (2x + 4)cm\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "It is given that its length is 4 cm more than 2 times its width\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So length of the rectangle = (2x + 4 ) cm.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Area of a rectangle is given by the formula, A = length * width\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Here area is given that 90 cm^2\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So we can write it as,\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "90 = (2x + 4 ) * x\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "==> 90 = 2x * x + 4 * x\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "==> 90 = 2x^2 + 4x\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Subtract 90 from both sides of the equation, then we will obtain a quadratic equation.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "==> 90 - 90 = 2x^2 + 4x - 90\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "==> 0 = 2x^2 + 4x - 90\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "2x^2 + 4x - 90 = 0\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We can solve this equation using quadratic formula.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "standard form of a quadratic equation is,\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "ax^2 + bx + c = 0 ---------------(2)\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "By quadratic formula, the solution is given by,\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Comparing (1) and (2) we have,\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "a = 2, b = 4 and c = -90\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "so the solution is,\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = (-4 + 27.129)/4 or x = (-4 - 27.129 )/4\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 23.129/4 or x = -41.129/4\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "( since negative values are not admisible here)\r \n" ); document.write( "\n" ); document.write( "==> x = 5.782 cm\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So width of the rectangle is 5.782 cm. \r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "so width = 5.782 cm.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "and length = 2x + 4 = 2 * (5.782) + 4 = 11. 564 + 4 = 15.564 cm\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So the dimenstions of the given rectangle:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "length = 15. 564 cm and\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Width = 5.782 cm.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "To check your answer, multiply lenth with breadth, then you will get 90 approximately.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Hope you understood.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Regards.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Praseena.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |