```>From:         Jim & Shirley <[log in to unmask]>

>>Denis Bogan wrote:

>> The comments about Ski Denton PA having "the steepest slope anywhere" got
> my attention so I did a search and turned up;
>
>> http://www.skidenton.com/
>
>> If you click on snow and then at the appropriate place on the trail map it
> describes a run called "Avalanche" which it says is the steepest in the
> east at 66 degrees.  To claim a figure like that is a dead give away that
> they don't know what steep is and don't know the difference between an
> angle in degrees and a % slope.  % slope = 100 X tangent of the angle.
> Arctan(.66) = 33 degrees, which is not half bad.

>Thanks for this interesting tidbit of information Denis.  Math was never my
forte in school so I wonder if this example is just coincidence that there
exists a 2 to 1 ratio of percent to degrees or can this comparison be used in
all cases?  ie:  70 percent slope = 35 degrees, 60 percent = 30, 50 percent =
25 etc.   Thanks     Jim

Good observation - I never noticed it.  That's coincidence but it's not bad
at all for slopes between 25 and 45 degrees, which is the range of greatest
concern to most of us.  For slopes steeper than 45 degrees the tangent (and
therefore the percent grade) increases rapidly and goes to infinity for a
90 degree slope.

Slope angle             Tangent (angle)         % Grade
25 deg          .47                             47
30                      .58                             58
35                      .70                             70
40                      .84                             84
45                      1.00                            100

Denis Bogan