document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1109038>Question 1109038</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If AB is the diameter of a circle with centre O (4,5) and A (8,3), find B. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #724056 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=724056\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Using the midpoint formula, as the other tutor suggested, is fine.  But plugging numbers into formulas usually doesn't teach you anything; it is perhaps more beneficial to you to solve the problem using a bit of logical reasoning.<br><BR>\n" );
document.write( "You know where the center of the circle is, at (4,5).  And you know one end point of a diameter is (8,3).<br><BR>\n" );
document.write( "To get from the center to the known end of a diameter, you move 4 units to the right (from 4 to 8) and 2 units down (from 5 to 3).<br><BR>\n" );
document.write( "So to get to the other end of that same diameter, from the center you need to do exactly the opposite: go 4 units to the left (from 4 to 0) and 2 units up (from 5 to 7).<br><BR>\n" );
document.write( "Answer: B is (0,7). </SPAN>\n" );
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