document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=563799>Question 563799</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Calculate angle A given the following information about triangle ABC. Calculate the side c using Cosine Law.\r<BR>\n" );
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document.write( "a=12, b=14, c=20 (there is exponent 0 beside the 20)\r<BR>\n" );
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document.write( "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 #365065 by </B><A HREF=/tutors/aboutme.mpl?userid=richard1234><B>richard1234(7193)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richard1234><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=richard1234><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=365065\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> You should know enough about angles to interpret \"c=20\" as \"20 degrees\" not \"20^0.\"\r<BR>\n" );
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document.write( "Draw the figure and label the sides/angles first. Then you can find side c using the cosine rule (also known as law of cosines)\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE c^2 = a^2 + b^2 - 2ab\cos(C) = 12^2 + 14^2 - 2*12*14*\cos(20^{\circ})\">\r<BR>\n" );
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document.write( "You can find c from there. You can't really use the law of cosines on angle A, but you can use the law of sines:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \frac{a}{\sin(A)} = \frac{c}{\sin(C)}\">\r<BR>\n" );
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document.write( "You know a = 12, C = 20 degrees, and you would have already found c. Hence replace these in to evaluate sin A, then take the arcsine of both sides. </SPAN>\n" );
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