document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=150945>Question 150945</A>: <I><SPAN STYLE=\"word-break: break-all;\"> find angle A  of the oblique triangle with sides a=13, b=14, and c=15 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #111053 by </B><A HREF=/tutors/aboutme.mpl?userid=mducky2><B>mducky2(62)</B></A><img src=\"/images/stars/stars-08.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mducky2><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=111053\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If you need to find an angle when three sides of an oblique triangle are known, use the law of cosines. The equation is:<BR>\n" );
document.write( "a<sup>2</sup> = b<sup>2</sup> + c<sup>2</sup> - 2bc cos A<BR>\n" );
document.write( "<br> Solve for A<BR>\n" );
document.write( "2bc cos A = b<sup>2</sup> + c<sup>2</sup> - a<sup>2</sup><BR>\n" );
document.write( "cos A = (b<sup>2</sup> + c<sup>2</sup> - a<sup>2</sup>)/(2bc)<BR>\n" );
document.write( "A = cos<sup>-1</sup>[(b<sup>2</sup> + c<sup>2</sup> - a<sup>2</sup>)/(2bc)]<BR>\n" );
document.write( "A = cos<sup>-1</sup>[(14<sup>2</sup> + 15<sup>2</sup> - 13<sup>2</sup>)/(2*14*15)]<BR>\n" );
document.write( "A = 53.13&deg </SPAN>\n" );
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