document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=12586>Question 12586</A>: <I><SPAN STYLE=\"word-break: break-all;\"> AB is a chord of a circle with centre O and is 40cm long. OD is drawn perpendicular to AB. If OD is 4.5cm in length, find the length of the radius of the circle. (all reasoning must be shown). thank you </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #6387 by </B><A HREF=/tutors/aboutme.mpl?userid=kusha><B>kusha(21)</B></A><img src=\"/images/stars/stars-07.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=kusha><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=6387\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> There is a theorm that a perpendicular to a chord from the centre of circle would bisect the chord.<BR>\n" );
document.write( "so the length of line segment AD is 20 cm and OD is 4.5 cm. Therefore using pythagoras theorm on triangle ADO we get\r<BR>\n" );
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document.write( "AOxAO = ODxOD + ADxAD\r<BR>\n" );
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document.write( "therefore AO  = Sq Rt(420.25) = the radius of circle </SPAN>\n" );
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