document.write( "Question 1006182: A triangle is defined by the three points:
\n" ); document.write( "A=(4,5)
\n" ); document.write( "B=(7,9)
\n" ); document.write( "C=(10,8)\r
\n" ); document.write( "\n" ); document.write( "Determine all three angles in the triangle(in radians) \n" ); document.write( "
Algebra.Com's Answer #622346 by Boreal(15235)\"\" \"About 
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Draw it helps. Here, side b is opposite angle B and is line AC; side c is BC, and side a is AB
\n" ); document.write( "b^2=a^2+c^2-2ac*cosB
\n" ); document.write( "45=25+10-2(sqrt (10)*5*cos B
\n" ); document.write( "10/10=-sqrt (10) cos B
\n" ); document.write( "sqrt(10)/10=-cos B
\n" ); document.write( "cos B= -sqrt(10)/10
\n" ); document.write( "=108.43 degrees
\n" ); document.write( "a^2=b^2+c^2-2bc cos A
\n" ); document.write( "25=45+10-2(sqrt450)) cos A
\n" ); document.write( "-30=-2(21.21) cos A
\n" ); document.write( "=45 degrees.
\n" ); document.write( "as a check, do
\n" ); document.write( "c^2=a^2+b^2-2ab cos C
\n" ); document.write( "10=25+45-2(5)(sqrt(45) cos C
\n" ); document.write( "-60= -2 *5 sqrt(45) cos C
\n" ); document.write( "6=sqrt 45 cos C
\n" ); document.write( "cos C=0.8944
\n" ); document.write( "=26.6 degrees
\n" ); document.write( "With rounding, essentially 180 degrees.
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