document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1194108>Question 1194108</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Given: tangents AB and AC to ⊙O<BR>\n" );
document.write( "  m∠ACB = 72°<BR>\n" );
document.write( "Find the following in degrees.<BR>\n" );
document.write( "mBC°\r<BR>\n" );
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document.write( "mBDC°\r<BR>\n" );
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document.write( "m∠ABC°\r<BR>\n" );
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document.write( "m∠A° </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #826219 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=826219\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Two tangents to a circle from the same point are congruent.  So triangle ABC is isosceles with base angles BCA and CBA and vertex angle  A.<br><BR>\n" );
document.write( "(1) Use that and the fact that the sum of the angles in a triangle is 180 degrees to find the measures of angle A and angle ABC.<br><BR>\n" );
document.write( "(2) The two tangents cut the 360 degrees of the circle into two parts.  If arc BC is x degrees, then the other arc is 360-x degrees.<br><BR>\n" );
document.write( "Then the measure of angle A is half the difference between the measures of the two arcs:<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A+=+%281%2F2%29%28%28360-x%29-x%29 ALIGN=MIDDLE  ALT=\"A+=+%281%2F2%29%28%28360-x%29-x%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "Use that and the measure of angle A that you found in part (1) to find x, which is the degree measure of arc BC.<br><BR>\n" );
document.write( "(3) It is impossible to find the measure of angle BDC, since point D is nowhere defined.<br><BR>\n" );
document.write( " </SPAN>\n" );
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