On graph paper, plot $ABCD$ if $A(0,3),B(2,5),C(6,3)$, and $D(4,1)$.  

1. Rotate $ABCD\ 90^\circ$ clockwise ($↻$) about the origin to form $A'B'C'D'$. Name the coordinates of $B'$.

   Answer (a):

   $(5, −2)$

2. Translate $A'B'C'D'$ up $8$ units and left $7$ units to form $A''B''C''D''$. Name the coordinates of $C''$.

   Answer (b):

   $(−4, 2)$

3. After rotating $ABCD$ $180^\circ$ to form $A'''B'''C'''D'''$, Arah noticed that the image lined up exactly with the original. In this case, about what point was $ABCD$ rotated? How did you locate it?