Geometry

Question Analysis：
This question asks you to identify the type of transformation applied to a shape.
The main focus is on recognizing a reflection across the y-axis using a graph.

Key Concept Explanation:
A reflection across the y-axis flips a figure horizontally over the y-axis.
Each point (x, y) becomes (−x, y), meaning:
The x-value changes sign
The y-value stays the same
Shape and size are preserved

Step-by-Step Solution：
Compare the black and red triangles.
They are mirror images on opposite sides of the y-axis.
The red figure is located the same vertical distance to the left of the y-axis as the black figure is to the right.
This confirms the transformation is a reflection across the y-axis.

Option Analysis：
A. Rotation ❌ No change in orientation that matches a circular motion.
B. Reflection across the x-axis ❌ That would flip the shape vertically (not seen here).
C. Reflection across the y-axis ✅ Correct – figure i...