Which term describes the flip of a figure over a line?

• A. Rotation
• B. Symmetry
• C. Vertex
• D. Reflection

Answer: (D)

Reflection is the flip of a figure over a line, like looking in a mirror. When you reflect a figure, every point moves straight to the other side of the line at the same distance from that line. The line you flip across—the line of reflection—acts as the axis of symmetry, and it sits at right angles to the segment joining each point with its image. The two shapes are congruent, and their orientation is reversed, which is why a mirror image looks flipped. It's different from rotation, which spins a figure around a point, and from a vertex, which is just a corner. Symmetry is a broader idea about balance or mirrored figures, but reflection is the exact action of flipping across a line.