[TowerTalk] Percent vs. Degree Grade - Not the same !

[Steve London]

I often see people throw around phrases on Towertalk, such as "my hill is a 10 
percent grade", or "my slope is a 10 degree grade". As I discovered in a 
wildland firefighting class, these are definitely not the same thing !  Just to 
clarify, so we are all on the same page:

Degree grade = arctan(height/distance)
Percent grade = (height/distance) * 100

So, for example, a 45 degree grade is the same thing as a 100 percent grade.

An easy-to-remember rule-of-thumb is that that the percent grade is about twice 
the degree grade.

It boggles my mind why we risk confusion and even talk about "percent grades". 
Isn't that why virtually every high-school graduate took geometry so we would 
have a better way to describe an angle ?

73,
Steve, N2IC