What you’ll learn
Recognize coordinate sign relationships.
Key idea
The coordinate parallel to the mirror axis stays fixed; the perpendicular coordinate changes sign.
Preserve the coordinate parallel to the mirror axis and negate only the perpendicular coordinate; reversing both is an origin reflection.
Worked example
Enter the exact value or ordered values in the format requested below.
A and its reflection B across the y-axis are plotted. Read B's ordered coordinates.
Marked coordinates: A=(-6, 2); B=(6, 2).
- Reflection across the y-axis preserves y and negates x.
- Thus A(-6,2) maps to B(6,2), the same perpendicular distance on the other side.
Answer: (6,2)
Quick Check
Construct or select a graph that correctly represents the data or relationship in 'Recognize coordinate sign relationships'.
Construct the reflection of A(-5,3) across the x-axis. Select B's location with its placement rule.