document.write( "Question 1191760: Cj needs to know the width of a river. He climbs a tree 10 meters high above the ground and finds that the angle of depression of the two opposite banks of the river is 40° and 15°, respectively. How wide is the river? \n" ); document.write( "
Algebra.Com's Answer #823590 by Theo(13342)\"\" \"About 
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the angle of depression of 15 forms a right triangle with the vertical leg of length 10 and the horizontal length of x + y.
\n" ); document.write( "tan(15) = 10 / (x + y)
\n" ); document.write( "solve for (x + y) to get:
\n" ); document.write( "(x + y) = 10 / tan(15) = 37.3205080\r
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\n" ); document.write( "\n" ); document.write( "the angle of depression of 40 forms a right triangle with the vertical leg of 10 and the horizontal length of x.
\n" ); document.write( "tan(40) = 10 / x
\n" ); document.write( "solve for x to get:
\n" ); document.write( "x = 10 / tan(40) = 11.91753593.\r
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\n" ); document.write( "\n" ); document.write( "y is equal to x + y minus x = 25.40297215.
\n" ); document.write( "that is the width of the river.\r
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\n" ); document.write( "\n" ); document.write( "let me know if you have any questions.
\n" ); document.write( "theo \n" ); document.write( "
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