document.write( "Question 1156439: The Mona Lisa is a famous painting by Leonardo da Vinci. The painting is 30 inches by 21 inches. It is surrounded by a frame of uniform thickness whose area (not including the center) is 756 inches squared. Find the thickness of the frame. \n" ); document.write( "

Algebra.Com's Answer #779132 by ikleyn(52777) $\"\"$ $\"About$

You can put this solution on YOUR website!
.
\n" ); document.write( "

\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "(21+2x)*(30+2x) - 21*30 = 756\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "60x + 42x + 4x^2 = 756\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "4x^2 + 102x - 756 = 0\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "x^2 + 51x - 378 = 0\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( " =  = .\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Negative root does not work.  The positive root  x =  = 6 is the solution to the problem.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "ANSWER.  6 inches.\r\n" );
document.write( "

\r
\n" ); document.write( "\n" ); document.write( "Solved.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "----------------\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "If you want to see many other similar solved problems, look into the lessons\r
\n" ); document.write( "\n" ); document.write( "    - Problems on the area and the dimensions of a rectangle surrounded by a strip\r
\n" ); document.write( "\n" ); document.write( "    - Cynthia Besch wants to buy a rug for a room \r
\n" ); document.write( "\n" ); document.write( "    - Problems on a circular pool and a walkway around it\r
\n" ); document.write( "\n" ); document.write( "in this site.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "The referred lesson is the part of this online textbook under the topic
\n" ); document.write( "\"Dimensions and the area of rectangles and circles and their elements\".\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );