document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1154497>Question 1154497</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The line y = x + 2 intersects the circle x2 + y2 = 10 in two points. Call the third- quadrant point R and the first-quadrant point E, and find their coordinates. Let D be the point where the line through R and the center of the circle intersects the circle again. The chord DR is an example of a diameter. Show that triangle RED is a right triangle.<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #776961 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13203)</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=776961\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "A rough sketch of the circle and line give a quick picture that makes it easy to solve the problem.<br><BR>\n" );
document.write( "You could easily find the points of intersection algebraically by substituting y=x+2 in the equation for the circle.<br><BR>\n" );
document.write( "However, a bit of simple mental arithmetic shows that the values of x and y, ignoring the signs, are 3 and 1; the rough sketch then determines that R is (-3,-1) and E is (1,3).<br><BR>\n" );
document.write( "Then, since RD is a diameter (cutting the circle into two 180-degree arcs), angle RED is 90 degrees.<br><BR>\n" );
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