The Lesson
A shape can be reflected in the x-axis. If point on a shape is reflected in the x-axis, the x-coordinate stays the same, but the y-coordinate changes sign (becomes negative if it is positive and vice versa). The image below shows a point on a shape being reflected in the x-axis:- The point A has Cartesian coordinates (3, 1).
- The reflected point A' has Cartesian coordinates (3, −1). The x-coordinate is still 3, but the y-coordinate has changed from 1 to −1.
How to Reflect a Shape in the X-Axis Using Cartesian Coordinates
Reflecting a shape in the x-axis using Cartesian coordinates is easy.Question
Reflect the shape below in the x-axis.Step-by-Step:
1
Find the Cartesian coordinates of each point on the shape.
Write the x-coordinates and y-coordinates of each point.
Point | x-coordinate | y-coordinate |
---|---|---|
A | 2 | 3 |
B | 5 | 2 |
C | 2 | 1 |
2
Find the Cartesian coordinates of the reflected points.
Keep the x-coordinate the same, but change the sign of the y-coordinate.
Point | x-coordinate | y-coordinate | Point | x-coordinate | y-coordinate |
---|---|---|---|---|---|
A | 2 | 3 | A' | 2 | −3 |
B | 5 | 2 | B' | 5 | −2 |
C | 2 | 1 | C' | 2 | −1 |
3
Plot the reflected points and draw in the shape.
Answer:
We have reflected the shape in the x-axis.A Formula to Reflect a Point in the X-Axis Using Cartesian Coordinates
In general, we write Cartesian coordinates as: x is the x-coordinate. y is the y-coordinate. x and y can taken any number. The reflected point has Cartesian coordinates:The image below shows a general Cartesian coordinate being reflected in the x-axis: