document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=184089>Question 184089</A>: <I><SPAN STYLE=\"word-break: break-all;\"> how do you find the center-radius form of the equation of a circle with center (4,-7) and tangent to the y-axis? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #138114 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=138114\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font face=\"Times New Roman\" size=\"+2\">\r<BR>\n" );
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document.write( "The equation of a circle with center at (<i>h</i>,<i>k</i>) and radius <i>r</i> is:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \text{          }\math (x - h)^2 + (y - k)^2 = r^2\">\r<BR>\n" );
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document.write( "You are given the center, (4,-7), and that the circle is tangent to the <i>y</i>-axis.  That means the radius is the distance from the <i>y</i>-axis to the center, or simply the value of the <i>x</i>-coordinate of the center, namely 4.  Substituting:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \text{          }\math (x - 4)^2 + (y + 7)^2 = 16\">\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=drawing%28%0D%0A500%2C+500%2C+-1%2C+12%2C+-12%2C+1%2C%0D%0Agrid%281%29%2C%0D%0Acircle%284%2C-7%2C4%29%2C%0D%0Acircle%284%2C-7%2C.1%29%2C%0D%0Alocate%284.1%2C-7.1%2CC%284%2C-7%29%29%2C%0D%0Acircle%280%2C-7%2C.1%29%2C%0D%0Alocate%28.1%2C-7.1%2CT%280%2C-7%29%29%0D%0Ablue%28line%28-.1%2C-7%2C-.1%2C-6%29%29%2C%0D%0Ablue%28line%284%2C-7%2C4%2C-6%29%29%2C%0D%0Ablue%28line%280%2C-6.5%2C4%2C-6.5%29%29%2C%0D%0Alocate%282%2C-6%2Cr=4%29%0D%0A%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<i>T</i> is the point of tangency.\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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