document.write( "Question 1089471: A man travels 5 km due north from his starting point and then travels a further 8 km in a straight line in the direction 30 degrees east of north.How far is he from his starting position ?
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Algebra.Com's Answer #703814 by Theo(13342)![]() ![]() You can put this solution on YOUR website! you could solve this by creating right triangles, or you can solve using the following formula:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "b^2 = a^2 + c^2 - 2 * a * c * cos(B)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this, i believe, is called the law of cosines.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "here's a reference:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "http://www.mathwarehouse.com/trigonometry/law-of-cosines-formula-examples.php\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "here's a picture of my worksheet.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " ![]() \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the triangle is labeled ABC.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "A is the starting point. \n" ); document.write( "B is the point 5 km due north. \n" ); document.write( "C is the point 8 km due 30 degrees east of north.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "angle B in the triangle is 150 degrees, since it is supplementary to the 30 degree angle.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "side a is opposite angle A of the triangle. \n" ); document.write( "side b is opposite angle B of the triangle. \n" ); document.write( "sice c is opposite angle C of the triangle.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this fits the law of cosines since you are looking for the side opposite the known angle and you have the measure of the side adjacent to that angle.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the worksheet has the details of the calculations.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "cos(150) is equal to -.8660254038\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the rest is just solving the equation.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "any questions, give me a shout.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "otherwise, i believe you have all that you need.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "another law that is sometimes useful is the law of sines.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "a reference to that can be found here:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "http://www.mathwarehouse.com/trigonometry/law-of-sines/formula-and-practice-problems.php\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |