In honor of Thanksgiving, here’s a funny comic from Incidental Comics comparing Pie and Pi.
[Source: Incidental Comics | Via Laughing Squid]
The infographic does not specify in what units the angles should be expressed such that the formulae work correctly.
As far as I am aware school curricula generally teach geometry based on degrees, so this would be the default unit used by most people.
Radians. Always radians.
Radians aren't really "units", either, but a ratio of length. The upshot is that ALL your variables are in the same units, which makes all your calculations so much easier.
They got the probability of the mincemeat pie being eaten completely wrong.
And isn't the remaining area ½(2π-θ?)r²