document.write( "Question 1204578: Here's another trig problem:
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Algebra.Com's Answer #840920 by math_tutor2020(3817)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "The original diagram \n" ); document.write( " ![]() \n" ); document.write( "The goal is to find the length of segment BC.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Use your favorite paint program to highlight triangle ABD. \n" ); document.write( " ![]() \n" ); document.write( "This is a right triangle because of the square angle marker at angle ADB. \n" ); document.write( "The reference angle is 8 degrees. \n" ); document.write( "Opposite the reference angle is AD = 10. \n" ); document.write( "Adjacent to the reference angle is BD. \n" ); document.write( "Let's use the tangent trig ratio to find side BD. \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Focus on triangle ABD only. \n" ); document.write( "tan(angle) = opposite/adjacent \n" ); document.write( "tan(B) = AD/BD \n" ); document.write( "tan(8) = 10/BD \n" ); document.write( "BD*tan(8) = 10 \n" ); document.write( "BD = 10/tan(8) \n" ); document.write( "BD = 71.153697223842 \n" ); document.write( "BD = 71.153697 \n" ); document.write( "This value is approximate. \n" ); document.write( "Please make sure that your calculator is set to degrees mode.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now let's highlight triangle ADC. \n" ); document.write( " ![]() \n" ); document.write( "We'll use tangent once again since triangle ADC is a right triangle. \n" ); document.write( "tan(angle) = opposite/adjacent \n" ); document.write( "tan(C) = AD/CD \n" ); document.write( "CD = AD/tan(C) \n" ); document.write( "CD = 10/tan(11) \n" ); document.write( "CD = 51.445540159703 \n" ); document.write( "CD = 51.445540\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The summary so far is that we found these approximate side lengths \n" ); document.write( "BD = 71.153697 \n" ); document.write( "CD = 51.445540 \n" ); document.write( "They will be used in the next part to find side BC.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The last thing to highlight is triangle BCD. \n" ); document.write( " ![]() \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Use the Law of Cosines. \n" ); document.write( "(BC)^2 = (BD)^2 + (CD)^2 - 2*(BD)*(CD)*cos(angle BDC) \n" ); document.write( "(BC)^2 = (71.153697)^2 + (51.445540)^2 - 2*(71.153697)*(51.445540)*cos(85) \n" ); document.write( "(BC)^2 = 7071.417954 \n" ); document.write( "BC = sqrt(7071.417954) \n" ); document.write( "BC = 84.09172 \n" ); document.write( "BC = 84\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "I rounded the final answer to the nearest whole number since the 10 cm given to us is a whole number. \n" ); document.write( "However, round that approximate value to some other level of precision if your teacher requires it. \n" ); document.write( " \n" ); document.write( " |