Trigonometry: What are Gradients?

[TSN79]

Just a simple wondering here, the calculator that comes with Windows XP (and other versions) have three choices for trigonometry, degrees, radians, and gradients. I have never heard of this last one, what is it?

 

[cristo]

It's a gradian-- a unit of angle such that the angle of a full circle is 400 gradians.

 

[Gib Z]

$$180 \mbox{degrees} = 200 \mbox{gradients} = \pi \mbox{radians} = \mbox{Angle of a Straight Line}$$

 

[HallsofIvy]

I think the real point is that 90 degrees= $\pi/2$ radians= 100 gradians. "1 grad" is 1 % of "straight up" and grads are typically used by highway engineers to measure slopes.

It is unfortunate that both "gradian" and "gradient" are abbreviated "grad"!