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Truckers (or engineers): What is the percentage of a grade based on?

In other words, if a grade is 6%, what is it 6% of? If someone told me something was inclined at a 45 degree angle, I would have a frame of reference - degrees of arc or an angle. But I have no idea what grade means. (I mean, practically I know we are talking about incline, I would just like to know what the math is.) Thanks!

2 Answers

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  • 10 years ago
    Favorite Answer

    You mention 45 deg angle. You know The tangent of 45 degrees is height over length ( Y over X). The tangent of 45 degrees is , you guessed it = 1.

    So if you have a 45 degree slope and the "X" is 100, then the "Y" = 100

    And therefore you have 100 over 100 = 1 times 100% = 100 % grade

    Wa la !!!!!!!!!!

  • Irv S
    Lv 7
    10 years ago

    'Percent', (out of 100) should give you a clue.

    It's feet of rise per hundred feet.

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