To rotate a point \( A(x, y) \) by 90 degrees counterclockwise around the origin, you can use the following transformation:
\[ (x', y') = (-y, x) \]
For the point \( A(2, 6) \):
- \( x = 2 \)
- \( y = 6 \)
Applying the transformation:
\[ x' = -y = -6 \] \[ y' = x = 2 \]
Thus, the new point after a 90-degree counterclockwise rotation would be:
\[ A'(-6, 2) \]
Therefore, after a 90-degree counterclockwise rotation, the new point on the triangle is \( A'(-6, 2) \).