document.write( "Question 1029851: Because of prevailing winds, a tree grew so that it was leaning 4 degrees from vertical. At a point 35 meters from the tree the angle of elevation to the top of the tree is 23 degrees. Find the height of the tree. \n" ); document.write( "
Algebra.Com's Answer #644901 by Theo(13342)\"\" \"About 
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the diagram i worked with is shown here.
\n" ); document.write( "look below the diagram for the discussion that follows.
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\n" ); document.write( "the right triangle formed is ACD.
\n" ); document.write( "the triangle formed that goes to the height of the tree is ABD.
\n" ); document.write( "drop a perpendicular from B to E on the line AD.
\n" ); document.write( "you have two right triangles formed.
\n" ); document.write( "they are ABE and DBE.
\n" ); document.write( "angle BAE is 23 degrees.
\n" ); document.write( "angle ABE is 67 degrees.
\n" ); document.write( "angle AEB is 90 degrees.
\n" ); document.write( "angle BDC is 4 degrees because this is the angle from the vertical that the tree is slanted at.
\n" ); document.write( "since angle CDE is a right angle, then angle BDE is 86 degrees.
\n" ); document.write( "since triangle DBE is a right triangle, than angle DBE is 4 degrees.
\n" ); document.write( "line BE is the altitude of both triangles ABE and DBE.
\n" ); document.write( "the line AD is broken up into two parts.
\n" ); document.write( "the first part is line AE whose length is designated as x.
\n" ); document.write( "the second part is line ED whose length is designated as 35-x.
\n" ); document.write( "AE and ED together form the line AD which is given as 35 meters long.
\n" ); document.write( "the length of the line BE is designated as h.\r
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\n" ); document.write( "\n" ); document.write( "from this we derive the following:\r
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\n" ); document.write( "\n" ); document.write( "tan(23) = h/x\r
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\n" ); document.write( "\n" ); document.write( "tan(86) = h/(35-x)\r
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\n" ); document.write( "\n" ); document.write( "solve for h in both these formulas and you get:\r
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\n" ); document.write( "\n" ); document.write( "h = x * tan(23)
\n" ); document.write( "h = (35-x) * tan(86)\r
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\n" ); document.write( "\n" ); document.write( "this gets you x * tan(23) = (35-x) * tan(86)
\n" ); document.write( "simplify this equation to get x * tan(23) = 35 * tan(86) - x * tan(86)
\n" ); document.write( "add x * tan(86) to both sides of this equation to get x * tan(23) + x * tan(86) = 35 * tan(86).
\n" ); document.write( "factor out the x to get x * (tan(23) + tan(86)) = 35 * tan(86).
\n" ); document.write( "divide both sides of this equation by (tan(23) + tan(86)) to get:
\n" ); document.write( "x = (35 * tan(86) / (tan(23) + tan(86)).
\n" ); document.write( "this results in x = 33.99107122.
\n" ); document.write( "this makes 35 - x = 1.008928777.\r
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\n" ); document.write( "\n" ); document.write( "h is calculated to be 33.99107122 * tan(23) and h is also calculated to be 1.008928777 * tan(86).\r
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\n" ); document.write( "\n" ); document.write( "both formulas tell you that h is equal to 14.42835371 meters.\r
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\n" ); document.write( "\n" ); document.write( "that's the height of the tree from the ground which is the length of line BE in the diagram.\r
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\n" ); document.write( "\n" ); document.write( "i believe the actual height of the tree would be the length of the line BD.\r
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\n" ); document.write( "\n" ); document.write( "that measures the length from the base of the tree to the top of the tree.\r
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\n" ); document.write( "\n" ); document.write( "that can be calculated based on the following formulas.\r
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\n" ); document.write( "\n" ); document.write( "sin(86) = BE / BD.
\n" ); document.write( "solve for BD to get BD = BE / sin(86).\r
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\n" ); document.write( "\n" ); document.write( "cos(86) = ED / BD.
\n" ); document.write( "solve for BD to get BD = ED / cos(86).\r
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\n" ); document.write( "\n" ); document.write( "BE^2 + ED^2 = BD^2 which makes BD = sqrt(BE^2 + ED^2).\r
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\n" ); document.write( "\n" ); document.write( "all of these point to the same length of the line BD which is equal to 14.46358628 meters.\r
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\n" ); document.write( "\n" ); document.write( "the vertical height of the tree is equal to 14.42835371 meters which is the length of the line BE.\r
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\n" ); document.write( "\n" ); document.write( "what i think is the actual height of the tree is equal to 14.46358628 meters which is the length of the line BD.\r
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\n" ); document.write( "\n" ); document.write( "that's what i get.\r
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