what is quadrant

A quadrant can also just be a quarter of any circle :)

This is what Alan is describing

Angles are often thought of as being in quadrants.  Angles between 0° and 90° are in the first quadrant; those between 90° and 180° are in the second quadrant; those between 180° and 270° are in the third quadrant and those between 270° and 360° are in the fourth quadrant.  

You could think of these as being quarters of a circle, taken anticlockwise.

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