Question

Which quadrant does the given angle 621 degrees lie?

Answer 1

`Q_3`

Explanation:

If I remember correctly, this was my way of finding the Q of any

`theta^o`:

Let q = int ( `theta/90` ) be the quotient from the division

`theta/90`.

If q is even and a multiple of 4, `theta in Q_1`;

otherwise `theta in Q_3`.

If q is odd and the remainder in ( q/4 ) is 1, `theta in Q_2`;

otherwise `theta in Q_4`.

Here, int ( 621/90 ) = 6 that is even but not a multiple of 4.

So, `621^o in Q_3`.

For that matter, int ( 711/90 )= 7 that is odd but not a multiple of 3. So,

`711^o in Q_4`,

Int ( 801/80 )= 8 that is even but a multiple of 4. So, `801^o in Q_1`

Int (891/80)= 9 that is odd but a multiple of 3. So, `891^o in Q_2`

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