Gradian or Grad
The gradian or grad, is the 'metric' angle, was Napoleon's attempt to impose order on measures of angle. 1 grad is defined as 1/100th of a right angle, and translates naturally to percentages.An angle of 50 grads is equal to half a right angle or 45 degrees.
An angle of 100 grads is a vertical line, measured fro the horizontal, and is equal to a right angle.
Grad is not the same as gradient. A 1 in 2 gradient, or 50% gradient, means along 2 and up 1, and is equal toi
\[tan^{-1}(1/2)=26.57\]
degrees, or 29.52 grads.