[racket] "error: degrees->complex: 360.0"

Hello all,

I can't figure this out as I have no function called degrees->complex and
it occurs only sometimes.  It's always when rotating stuff through the
positive x axis, as in it's probably related to floating point operations
like sin or cos near 0 or perhaps integer multiples of 2pi.  So far I
believe it has only happened rotating clockwise where the error freezes the
program with slightly negative radians displaying (part of my debug output).

It's possible it's my own bug with a bad sqrt or using NaN or something,
but then what does the message mean?
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