Need the area of a broken polygon?
Don't bother fixing it.
Just sum up the cross product of the two endpoints, and divide by two.
[Here u × v := u₁v₂ − u₂v₁. Works even if the polygon is nonconvex. Caveat: all segments must point counter-clockwise, since u × v = −v × u!]
@keenancrane Assuming the center of the original polygon was at the origin.
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@pdstarrett
I am pretty sure this works even if it is offset from the origin. I have heard this called the shoelace method(since if you line up the x and y coordinates of all the points the added and subtracted terms zigzag)
@keenancrane
