The set of transformation that proves that the shapes are congruent are a rotation 90° about the origin and a reflection about the y-axis which can be represented as follows;

The steps used to find the set of transformation that proves that the shapes are congruent are presented as follows;
The coordinates of the vertices of the original shape and the new shape indicates that the transformation from the original shape to the new shape is; (x, y) → (-y, -x)
The transformation (x, y) → (-y, -x) corresponds to a rotation of 90° clockwise about the origin(x, y) → (y, -x), followed by a reflection about the y-axis (y, -x) → (-y, -x)
The coordinates of the image are therefore;
Transformation; Rotation 90° Clockwise about the Origin
(2, 5) → Rotation 90° Clockwise about the Origin → (5, -2)
(2, 3) → Rotation 90° Clockwise about the Origin → (3, -2)
(7, 3) → Rotation 90° Clockwise about the Origin → (3, -7)
Transformation; Reflection about the y-axis
(5, -2) → Transformation → (-5, -2)
(3, -2) → Transformation → (-3, -2)
(3, -7) → Transformation → (-3, -7)
The coordinates of the above image corresponds with the coordinated os the vertices of the image of the original triangle
The vertices of the possible triangles obtained from a similar question found through search are;
Original shape (2, 5), (2, 3), (7, 3)
New shape (-5, -2), (-3, -2), (-3, -7)