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A motorcycler daredevil is planning a stunt to perform at a county fair.  A ramp must...

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mpumpkin | Valedictorian

Posted May 14, 2013 at 10:41 AM via web

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A motorcycler daredevil is planning a stunt to perform at a county fair.  A ramp must be built to give him a 20% grade, or slope.  If the vertical height at the end of the ramp must be 19ft to assure that the stunt is a sucess, what must be the length of the horizontal run? 

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mjripalda | High School Teacher | (Level 3) Educator

Posted May 14, 2013 at 10:56 AM (Answer #1)

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To solve, apply the formula:

`g r a d e = (rise)/(run) *100`

In the the problem, the rise represents the height of the ramp. So, to determine the horizontal run, plug-in grade=20 and rise=19  to the formula. Also, let x be the horizontal run.

`20=19/x*100`

`20=1900/x`

Then, multiply both sides by x.

`20*x=1900/x*x`

`20x=1900`

And, divide both sides by 20.

`(20x)/20=1900/20`

`x=95`

Hence, the horzontal run of the ramp is 95 feet.

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