document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=193915>Question 193915</A>: <I><SPAN STYLE=\"word-break: break-all;\"> PLEASE HELP ME WITH THIS!\r<BR>\n" );
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document.write( "Use the given information to write an equation of the circle.\r<BR>\n" );
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document.write( "16. radius 3, center (2, 4)<BR>\n" );
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document.write( "17. area 12.57, center (1, -2)\r<BR>\n" );
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document.write( "18. center (5, -1), circumference 5p \r<BR>\n" );
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document.write( "19. center (0, 0), passing through (2, 0) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #145645 by </B><A HREF=/tutors/aboutme.mpl?userid=solver91311><B>solver91311(24713)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=solver91311><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=solver91311><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=145645\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font face=\"Garamond\" size=\"+2\">\r<BR>\n" );
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document.write( "Writing the equation of a circle is a simple matter of plugging in values once you have the coordinates of the center and the radius.\r<BR>\n" );
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document.write( "A circle with center at <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large (h,k)\"> and radius <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large r\">\r<BR>\n" );
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document.write( "is:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \ \ \ \ \ \ \ \ \ \ (x - h)^2 + (y - k)^2 = r^2\">\r<BR>\n" );
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document.write( "So for your problem 16, just stick in the values:\r<BR>\n" );
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document.write( "radius 3, center (2, 4)\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \ \ \ \ \ \ \ \ \ \ (x - 2)^2 + (y - 4)^2 = 9\">\r<BR>\n" );
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document.write( "Then, depending on the form your instructor or your textbook wants, you might want to expand the binomials:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \ \ \ \ \ \ \ \ \ \ x^2 - 4x + 4 + y^2 - 8y + 16 = 9\">\r<BR>\n" );
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document.write( "And collect terms:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \ \ \ \ \ \ \ \ \ \ x^2 + y^2 - 4x - 8y + 11 = 0\">\r<BR>\n" );
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document.write( "17.  Works the same way, except that here you are given the area instead of the radius, but we know that the area equals <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large \pi r^2\">, so the radius squared is simply the area divided by <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large \pi\">.\r<BR>\n" );
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document.write( "18.  This time you have the circumference instead of the radius, but we know that <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large C = 2\pi r\">  so divide the circumference by <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large 2\pi\"> and square the result to get <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large r^2\">\r<BR>\n" );
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document.write( "19.  The distance between the center of a circle and any point on the circle is the radius.  When you have two points and want to know the distance between them, use the distance formula:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \ \ \ \ \ \ \ \ \ \ d = sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}\">\r<BR>\n" );
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document.write( "where <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large (x_1,y_1)\"> and <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large (x_2,y_2)\"> are the coordinates of the given points.\r<BR>\n" );
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document.write( "But you can save a couple of calculation steps if you realize that what you really need for the equation of your circle is <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large r^2\"> which is the same as <IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\Large d^2\">, so:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \ \ \ \ \ \ \ \ \ \ d^2 = (x_1 - x_2)^2 + (y_1 - y_2)^2\">\r<BR>\n" );
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document.write( "John<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE e^{i\pi} + 1 = 0\"><BR>\n" );
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