Reflections: find the coordinates

A reflection flips a figure across a line to create a mirror image.

When a point is reflected across the y-axis, the x-coordinate changes sign.

Learn with an example

Start with the point G(4, 1) and the y-axis.

Reflect the point across the line.

Since G is 4 units to the left of the y-axis, G′ is 4 units to the right of the y-axis. G′ has coordinates (4, 1).

E ‘=(____ , ____)

Start with the point E(1, 2) and the x-axis.

Reflect the point across the line.

Since E is 2 units above the x-axis, E′ is 2 units below the x-axis. E′ has coordinates (1, 2).

Start with the point E(2, 6) and the y-axis.

Reflect the point across the line.

Since E is 2 units to the left of the y-axis, E′ is 2 units to the right of the y-axis. E′ has coordinates (2, 6).

let’s practice!