document.write( "Question 994013: related rates problem:\r
\n" ); document.write( "\n" ); document.write( "The spool of a kite is held fixed at 5 feet above the ground. The kite is 105 feet above the ground and traveling eastward in a horizontal fashion. The string is being let out at 2ft/sec. Find the horizontal speed of the kite when 125 feet of string are let out.\r
\n" ); document.write( "\n" ); document.write( "Please explain how to set one of these type problems up. Very confused here.
\n" ); document.write( "Thank you\r
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Algebra.Com's Answer #613271 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
The spool of a kite is held fixed at 5 feet above the ground. The kite is 105 feet above the ground and traveling eastward in a horizontal fashion. The string is being let out at 2ft/sec. Find the horizontal speed of the kite when 125 feet of string are let out.
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\n" ); document.write( "Draw the picture::
\n" ); document.write( "You have a right triangle with spool at (0,5), base = h, height = 100,
\n" ); document.write( "hypotenuse = string = s
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\n" ); document.write( "h^2 = s^2-100^2
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\n" ); document.write( "h = sqrt[s^2-100^2)
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\n" ); document.write( "dh/ds = (1/2)(s^2-100^2)^(-1/2)*(2s)
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\n" ); document.write( "dh/ds = s/sqrt[s^2-100^2)
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\n" ); document.write( "h'(125) = 125/sqrt[125^2-100^2] = 125/75 = 5/3 = 1.67 ft/sec
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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