



 
Hi Brian. Radians are not true units, just as percentages aren't true units. A radian is simply an angle or a part of a circle. We have ten fingers and ten toes (usually) so we like base 10. That makes percentages (fractions out of 100) particularly convenient. With cycles (circles, periods, revolutions, angular measurements), we find it easiest to work not in 100ths of a whole but in "2 piths" of a whole. So they are really just a particular kind of fraction. Cheers,  


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