To determine which transformation will result in a rectangle that is NOT congruent to the original rectangle, we need to analyze each transformation:
a. A dilation by a scale factor of 3: This transformation increases the size of the rectangle by a factor of 3, which means the new rectangle will have different dimensions and will not be congruent to the original rectangle.
b. A rotation of 180° counterclockwise: This transformation will change the orientation of the rectangle but will not change its size or shape, so the new rectangle will be congruent to the original.
c. A translation of 90 units to the right: This transformation shifts the rectangle's position without altering its size or shape, so the new rectangle will be congruent to the original.
d. A reflection across the x-axis: This transformation flips the rectangle over the x-axis, but it will still be the same size and shape, so the new rectangle will be congruent to the original.
Conclusion: The only transformation that results in a rectangle that is NOT congruent to the original rectangle is a. a dilation by a scale factor of 3.