document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1159265>Question 1159265</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The sides of a triangle measure 18 in, 25 in, and 36 in. To the nearest degree, what is the measure of the largest angle? (also I think this has to do with the law of cosines?)\r<BR>\n" );
document.write( "\n" );
document.write( "Multiple choice:<BR>\n" );
document.write( "A. 113 degrees<BR>\n" );
document.write( "B. 157 degrees<BR>\n" );
document.write( "C. 147 degrees<BR>\n" );
document.write( "D. 159 degrees\r<BR>\n" );
document.write( "\n" );
document.write( "Thank you so much :) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #782240 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><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=782240\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font color=black size=3><BR>\n" );
document.write( "You are correct. You'll use the law of cosines to find the largest angle.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "The largest angle is always opposite the longest side of any triangle. The largest side is 36 inches<BR>\n" );
document.write( "a = 18<BR>\n" );
document.write( "b = 25<BR>\n" );
document.write( "c = 36\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Let angles A,B,C be opposite sides a,b,c in that exact order. We want to find angle C as its opposite the longest side c = 36\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Law of cosines<BR>\n" );
document.write( "c^2 = a^2 + b^2 - 2*a*b*cos(C)<BR>\n" );
document.write( "(36)^2 = (18)^2 + (25)^2 - 2*(18)*(25)*cos(C)<BR>\n" );
document.write( "1296 = 324 + 625 - 900*cos(C)<BR>\n" );
document.write( "1296 = 949 - 900*cos(C)<BR>\n" );
document.write( "1296 - 949 = 949 - 900*cos(C)-949<BR>\n" );
document.write( "347  = -900*cos(C)<BR>\n" );
document.write( "(347)/(-900)  = (-900*cos(C))/(-900)<BR>\n" );
document.write( "-0.385555555555556 = cos(C)<BR>\n" );
document.write( "cos(C) = -0.385555555555556<BR>\n" );
document.write( "arccos(cos(C)) = arccos(-0.385555555555556)<BR>\n" );
document.write( "C = 112.678234158676<BR>\n" );
document.write( "C = 113  after rounding to the nearest whole number\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "<font color=red size=4>Answer: A. 113 degrees (approximately)</font><BR>\n" );
document.write( "</font> </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );