document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=197653>Question 197653</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a rectangular lawn is 80 ft by 60ft.  part of the lawn is torn up to install a sidewalk of equal width around the lawn.  The new area of the lawn is 800 ft^2.  how wide is the sidewalk?\r<BR>\n" );
document.write( "\n" );
document.write( "Hi - I can't figure this out.  I know the area of the first rectangle is 4800 ft^2.  Once I reduce the lawn I think the length is 40 ft and the length is 20 ft.  That leaves 4000 ft of area.  I don't konw how to find the width of the sidewalk.  Thanks for your help.<BR>\n" );
document.write( "This is not from a textbook but a worksheet my teacher gave us. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #148203 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=148203\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a rectangular lawn is 80 ft by 60ft.  part of the lawn is torn up to install a sidewalk of equal width around the lawn.  The new area of the lawn is 800 ft^2.  how wide is the sidewalk?<BR>\n" );
document.write( "--------------<BR>\n" );
document.write( "Draw the picture of a rectangle inside a rectangle.<BR>\n" );
document.write( "The outer triangle is 80 by 60 = 4800 sq ft.<BR>\n" );
document.write( "-----------------<BR>\n" );
document.write( "Let the width of the sidewalk be \"x\"<BR>\n" );
document.write( "-----------------<BR>\n" );
document.write( "The inner rectangle has dimensions 80-2x and 60-2x<BR>\n" );
document.write( "The area of the inner rectangle is (80-2x)(60-2x) = 4800 -120x -160x + 4x^2<BR>\n" );
document.write( "-----------------------------------<BR>\n" );
document.write( "Equation:<BR>\n" );
document.write( "Area of the inner rectangle = 4x^2 - 280x +4800 = 800 sq. ft.<BR>\n" );
document.write( "Simplify and solve:<BR>\n" );
document.write( "x^2 - 70x + 1000 = 0<BR>\n" );
document.write( "(x-20)(x-50) = 0<BR>\n" );
document.write( "Realistic answer:<BR>\n" );
document.write( "x = 20 ft (width of the sidewalk)<BR>\n" );
document.write( " ----------------<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );