📚 Topic Summary
Reflections across horizontal and vertical lines are transformations that create a mirror image of a point or shape. When reflecting across a horizontal line (like $y = a$), the x-coordinate stays the same, and the y-coordinate changes. Similarly, reflecting across a vertical line (like $x = b$), the y-coordinate remains the same, and the x-coordinate changes. Understanding how coordinates transform is key to mastering reflections!
🧮 Part A: Vocabulary
Match the term with its definition:
| Term |
Definition |
| 1. Reflection |
A. The line that acts as a mirror. |
| 2. Line of Reflection |
B. A transformation that flips a figure over a line. |
| 3. Pre-image |
C. The new figure created by a transformation. |
| 4. Image |
D. The original figure before a transformation. |
| 5. Coordinate Plane |
E. A plane formed by the intersection of a horizontal number line (x-axis) and a vertical number line (y-axis). |
Match the correct term with the definition.
✍️ Part B: Fill in the Blanks
Complete the paragraph using the words: horizontal, vertical, x-coordinate, y-coordinate, reflection.
A ______ is a transformation that creates a mirror image. When reflecting over a ______ line, the ______ remains the same. Conversely, when reflecting over a ______ line, the ______ remains the same.
🤔 Part C: Critical Thinking
Explain, in your own words, how reflecting a point across $y = x$ differs from reflecting a point across the y-axis.