document.write( "Question 1151811: A= 25 degrees
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document.write( "a=5
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document.write( "b=11\r
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document.write( "Solve the triangle ABC\r
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document.write( "Thank you!! \n" );
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Algebra.Com's Answer #773670 by jim_thompson5910(35256)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "Angles \n" ); document.write( "A = 25 \n" ); document.write( "B = unknown \n" ); document.write( "C = unknown\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Sides \n" ); document.write( "a = 5 \n" ); document.write( "b = 11 \n" ); document.write( "c = unknown\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We have two known sides an angle that is not between the two sides. This is the SSA case which has 3 possibilities
\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Use the law of sines to solve for angle B \n" ); document.write( "sin(A)/a = sin(B)/b \n" ); document.write( "sin(25)/5 = sin(B)/11 \n" ); document.write( "0.0845236523481399 = sin(B)/11 \n" ); document.write( "11*0.0845236523481399 = 11*sin(B)/11 \n" ); document.write( "0.929760175829539 = sin(B) \n" ); document.write( "sin(B) = 0.929760175829539 \n" ); document.write( "arcsin(sin(B)) = arcsin(0.929760175829539) \n" ); document.write( "B = arcsin(0.929760175829539) or B = 180 - arcsin(0.929760175829539) \n" ); document.write( "B = 68.3974616057519 or B = 111.602538394248 \n" ); document.write( "B = 68.397 or B = 111.603\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If B = 68.397, then C = 180-A-B = 180-25-68.397 = 86.603 \n" ); document.write( "If B = 111.603, then C = 180-A-B = 180-25-111.603 = 43.397 \n" ); document.write( "In either case, the value of B produces a positive C value. Therefore, we have two sets of solutions to represent the two possible triangles.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "With this info: C = 86.603, a = 5, b = 11, we can find the unknown side c using the law of cosines \n" ); document.write( "c^2 = a^2 + b^2 - 2*a*b*cos(C) \n" ); document.write( "c^2 = (5)^2 + (11)^2 - 2*(5)*(11)*cos(86.603) \n" ); document.write( "c^2 = 25 + 121 - 110*0.0592541057795245 \n" ); document.write( "c^2 = 25 + 121 - 6.51795163574769 \n" ); document.write( "c^2 = 139.482048364252 \n" ); document.write( "c = sqrt(139.482048364252) \n" ); document.write( "c = 11.8102518332274 \n" ); document.write( "c = 11.810\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So one solution consists of \n" ); document.write( "Angles \n" ); document.write( "A = 25 \n" ); document.write( "B = 68.397 \n" ); document.write( "C = 86.603 \n" ); document.write( "Sides \n" ); document.write( "a = 5 \n" ); document.write( "b = 11 \n" ); document.write( "c = 11.810\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "--------------------------------------------------\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Use the law of cosines again, but now with C = 43.397 \n" ); document.write( "The values of 'a' and b stay the same \n" ); document.write( "c^2 = a^2 + b^2 - 2*a*b*cos(C) \n" ); document.write( "c^2 = (5)^2 + (11)^2 - 2*(5)*(11)*cos(43.397) \n" ); document.write( "c^2 = 25 + 121 - 110*0.726610645792925 \n" ); document.write( "c^2 = 25 + 121 - 79.9271710372218 \n" ); document.write( "c^2 = 66.0728289627782 \n" ); document.write( "c = sqrt(66.0728289627782) \n" ); document.write( "c = 8.12851948160169 \n" ); document.write( "c = 8.129\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The other solution consists of \n" ); document.write( "Angles \n" ); document.write( "A = 25 \n" ); document.write( "B = 111.603 \n" ); document.write( "C = 43.397 \n" ); document.write( "Sides \n" ); document.write( "a = 5 \n" ); document.write( "b = 11 \n" ); document.write( "c = 8.129\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "--------------------------------------------------\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "In summary, the two possible triangles are \n" ); document.write( "
\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Diagram \n" ); document.write( " ![]() \n" ); document.write( "The decimal values are approximate to three decimal places. \n" ); document.write( " \n" ); document.write( " |