National Council of Teachers of Mathematics
The Math Forum: Line Symmetry
This site from The Math Forum is a great site if you are looking for activities to engage your students in learning about line symmetry. Peruse this collection of activities for one or two or four that would be right for your students....
The Math League
The Math League: Symmetric Figure
This tutorial features several examples of symmetric figures to explain how the line of symmetry works.
Other
Ic Teachers: Line or Reflective Symmetry
This website will provide you with a quick review of line or reflective symmetry. It also has questions and answers to help you understand line/reflective symmetry.
University of Cambridge
University of Cambridge: Nrich: Symmetry Challenge
Sharpen your logic, symmetry, and pattern recognition skills while working on this challenge. Solution included.
University of Cambridge
University of Cambridge: Nrich: Happy Halving
On this one page website expand your logic, symmetry and pattern recognition knowledge while working on this challenge. The solution is available to double check your solution.