Answer:
Given the coordinates of triangle ABC are A(2,-1), B(4,1), C(3,3) and coordinates of triangle A'B'C' are A'(1,2), B'(-1,4), C'(-3,3).
To find the rotation rule that verifies that the triangle ABC and A'B'C' are congruent.
The rule of rotation of 90 degree counterclockwise is given by:
![(x, y) \rightarrow (-y, x)](https://img.qammunity.org/2019/formulas/mathematics/high-school/yto2t909o9gyncvybcj5ofq3bkwlksoxx5.png)
![A(2, -1) \rightarrow (-(-1), 2)=(1, 2) =A'](https://img.qammunity.org/2019/formulas/mathematics/high-school/8pqa8p8pgabhyypsp20dqwf01go9bqt3dt.png)
![B(4, 1) \rightarrow (-1, 4)=B'](https://img.qammunity.org/2019/formulas/mathematics/high-school/uwhkpgmnrcv7iekfcfbvdh1my0nm9s22uh.png)
![C(3, 3) \rightarrow (-3, 3)=C'](https://img.qammunity.org/2019/formulas/mathematics/high-school/8jcg2kqaxxebaxidp23x1ardsvey4iopan.png)
Therefore, the rotation rule that verifies that the triangle ABC and A'B'C' are congruent is
![(x, y) \rightarrow (-y, x)](https://img.qammunity.org/2019/formulas/mathematics/high-school/yto2t909o9gyncvybcj5ofq3bkwlksoxx5.png)