document.write( "Question 765370: From a ship, the angle of elevation of a point A at the top of a cliff is 21 degrees after the ship has sailed 2500m directly toward the foot of the cliff, the angle of elevation of A is 47 degrees. Find the height of the cliff. \n" ); document.write( "
Algebra.Com's Answer #466111 by Cromlix(4381)\"\" \"About 
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Point B is where the 21 degree angle of elevation was taken.
\n" ); document.write( "Point C is where the 47 degree angle of elevation was taken.
\n" ); document.write( "Point D is at the base of the cliff.
\n" ); document.write( "You now have a large triangle ABD
\n" ); document.write( "Two smaller triangles ABC and ACD
\n" ); document.write( "Putting in angles: Angle BCA = 133 degrees,
\n" ); document.write( "Angle BAC = 26 degrees
\n" ); document.write( "Considering triangle ABC:
\n" ); document.write( "a/Sin A = b/Sin B
\n" ); document.write( "2500/sin(26) = b/Sin(21)
\n" ); document.write( "Cross multiply.
\n" ); document.write( "(2500 * sin(21))/sin(26) = b
\n" ); document.write( "b (Side AC) = 2043.75m
\n" ); document.write( "Considering triangle ACD
\n" ); document.write( "This is right angled at D
\n" ); document.write( "sin = Opposite/Hypotenuse.
\n" ); document.write( "sin(47) = Opposite/2043.75
\n" ); document.write( "Opposite = sin(47) * 2043.75
\n" ); document.write( "Opposite = 1494.7m
\n" ); document.write( "This is the height of the cliff.
\n" ); document.write( "Hope this helps.
\n" ); document.write( ":-)
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