document.write( "Question 1043572: 1. A ship leaves a port and sails for 4 hours on a course of 78° at 18 knots. Then the ship changes it's course to 128° and sails for 6 hours at 16 knots. Find 10 hours after leaving the port:
\n" ); document.write( "*the distance of ship from the part
\n" ); document.write( "*the bearing of the ship from the port
\n" ); document.write( "*the bearing from the ship to the port.\r
\n" ); document.write( "\n" ); document.write( "2. A ship is sailing due west when a light is observed with heading 297°50' from the ship. After the ship has travelled 2250 feet, the light heads 311°55' from the ship. If the course is continued, how close will the ship approach the light?\r
\n" ); document.write( "\n" ); document.write( "Please provide illustrations so I could study it. Thank you.
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Algebra.Com's Answer #659159 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
1. I had to look up the definition of course, heading, and bearing,
\n" ); document.write( "and what I found is some confusion.
\n" ); document.write( "In most sources They were defined as the angle from North to the direction the ship is aiming for, or pointing to,
\n" ); document.write( "measured clockwise from North.
\n" ); document.write( "I am sticking to that, but I believe that for the first problem, it does not matter how you measure the angle, as long as it is done consistently.
\n" ); document.write( "
\n" ); document.write( "\"%284hours%29%2A%2818knots%29=72\"\"nautical\"\"miles\"
\n" ); document.write( "\"%286hours%29%2A%2816knots%29=96\"\"nautical\"\"miles\" .
\n" ); document.write( "The situation can be sketched like this:
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\n" ); document.write( "The right triangles with a red hypotenuse of length \"red%2872%29\" have legs measuring
\n" ); document.write( "\"x%5B1%5D=72%2Asin%2878%5Eo%29=70.42663\" (rounded to 5 decimal places) and
\n" ); document.write( "\"y%5B1%5D=72%2Acos%2878%5Eo%29=14.96964\" (rounded to 5 decimal places) .
\n" ); document.write( "At \"4\" hours the ship was about 70 nautical miles East, and 15 miles North of the port.
\n" ); document.write( "The legs of the right triangles with a green hypotenuse of length \"green%2896%29\" are such that
\n" ); document.write( "\"x%5B2%5D=96%2Asin%28128%5Eo%29=75.64903\" (rounded to 5 decimal places) and
\n" ); document.write( "\"-y%5B2%5D=96%2Acos%28128%5Eo%29=-59.1035\" (rounded to 5 decimal places) .
\n" ); document.write( "After \"4%2B6=10\" hours the ship was about 76 nautical miles further East, and 59 miles South from its position at \"4\" hours.
\n" ); document.write( "
\n" ); document.write( "Considering only the start and end positions, we have
\n" ); document.write( "
\n" ); document.write( "We have one right triangle, and we know the legs, so we can find
\n" ); document.write( "the hypotenuse, and
\n" ); document.write( "angle \"theta\" .
\n" ); document.write( "The lengths of the legs are approximately
\n" ); document.write( "\"x%5B1%5D%2Bx%5B2%5D=70.42663%2B75.64903=146.07566\" and ;
\n" ); document.write( "\"tan%28theta%29=44.13386%2F144.07566=0.30201\"--->\"theta=163.8%5Eo\" .
\n" ); document.write( "So,
\n" ); document.write( "the distance to the ship from the port is \"highlight%28152.6%29\" nautical miles,
\n" ); document.write( "the bearing of the ship from the port is \"90%5Eo%2B16.8%5Eo=highlight%28106.8%5Eo%29\" , and
\n" ); document.write( "the bearing from the ship to the port is
\n" ); document.write( "\"270%5Eo%2B16.8%5Eo=highlight%28286.8%5Eo%29\" .
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\n" ); document.write( "2. The ship is going West.
\n" ); document.write( "When the ship reaches point \"A\" it records the bearing/heading of the light,
\n" ); document.write( "and it does it again, \"2250\" feet further, at point \"B\" .
\n" ); document.write( "If the course is continued, \"x\" feet further, the ship will reach point \"C\" ,
\n" ); document.write( "where it is at a distance of \"d\" feet from the light,
\n" ); document.write( "as close to the light as its westward trajectory would take it.
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\n" ); document.write( "We have two right triangles: \"ALC\" and \"BLC\" .
\n" ); document.write( "For triangle \"ALC\" , a leg measuring \"d\" feet is opposed to an angle measuring \"297%5Eo\"\"%2250+%27%22-270%5Eo=27%5Eo\"\"%2250+%27%22=approximately27.83333%5Eo\" ,
\n" ); document.write( "while leg measuring \"x%2B2250\" feet is adjacent to the same angle.
\n" ); document.write( "So, \"tan%2827.83333%5Eo%29=d%2F%28x%2B2250%29\" .
\n" ); document.write( "For triangle \"BLC\" , a leg measuring \"d\" feet is opposed to an angle measuring \"311%5Eo\"\"%2255+%27%22-270%5Eo=41%5Eo\"\"%2255+%27%22=approximately41.91667%5Eo\" ,
\n" ); document.write( "while leg measuring \"x\" feet is adjacent to the same angle.
\n" ); document.write( "So, \"tan%2841.91667%5Eo%29=d%2Fx\" .
\n" ); document.write( "Dividing one equation vby the other, we get
\n" ); document.write( "\"tan%2841.91667%5Eo%29%2Ftan%2827.83333%5Eo%29=%28x%2B2250%29%2Fx\" ,which can be solved for \"x\" .
\n" ); document.write( "Then, we can use \"tan%2841.91667%5Eo%29=d%2Fx\"<--->\"d=x%2Atan%2841.91667%5Eo%29\" to find \"d\" .
\n" ); document.write( "Solving:
\n" ); document.write( "\"tan%2841.91667%5Eo%29%2Ftan%2827.83333%5Eo%29=%28x%2B2250%29%2Fx\"
\n" ); document.write( "\"x%2Atan%2841.91667%5Eo%29%2Ftan%2827.83333%5Eo%29=x%2B2250\"
\n" ); document.write( "\"x%2Atan%2841.91667%5Eo%29%2Ftan%2827.83333%5Eo%29-x=2250\"
\n" ); document.write( "\"x%28tan%2841.91667%5Eo%29%2Ftan%2827.83333%5Eo%29-1%29=2250\"
\n" ); document.write( "\"x%28tan%2841.91667%5Eo%29-tan%2827.83333%5Eo%29%29%2Ftan%2827.83333%5Eo%29=2250\"
\n" ); document.write( "\"x%28tan%2841.91667%5Eo%29-tan%2827.83333%5Eo%29%29=2250%2Atan%2827.83333%5Eo%29\"
\n" ); document.write( "\"x=2250%2Atan%2827.83333%5Eo%29%2F%28tan%2841.91667%5Eo%29-tan%2827.83333%5Eo%29%29\" ,
\n" ); document.write( "and finally
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\n" ); document.write( "That calculates as approximately
\n" ); document.write( "\"d=highlight%282884%29\" feet.
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