document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=873923>Question 873923</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need to find X in a 90 degree triangle with sides X, X+7, and 13. The hypotenuse is the side with 13.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #527183 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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/cgi-bin/show-face.mpl?user=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=527183\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I need to find X in a 90 degree triangle with sides X, X+7, and 13. The hypotenuse is the side with 13. <BR>\n" );
document.write( "Because one angle of the triangle is 90 degrees, you have a \"right triangle\".  Since it is a right triangle, you can apply Pythagorean theorem:<BR>\n" );
document.write( "a^2 + b^2 = c^2<BR>\n" );
document.write( "where<BR>\n" );
document.write( "a, b are the legs<BR>\n" );
document.write( "and<BR>\n" );
document.write( "c is the hypotenuse<BR>\n" );
document.write( ".<BR>\n" );
document.write( "x^2 + (x+7)^2 = 13^2<BR>\n" );
document.write( "x^2 + x^2+14x+49 = 169<BR>\n" );
document.write( "2x^2+14x+49 =169<BR>\n" );
document.write( "2x^2+14x-120 = 0<BR>\n" );
document.write( "x^2+7x-60 = 0<BR>\n" );
document.write( "(x+12)(x-5) = 0<BR>\n" );
document.write( "x = {-12, 5}<BR>\n" );
document.write( "throw out the negative solution (extraneous) leaving<BR>\n" );
document.write( "x = 5 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );