There are 3 lines of symmetry.
The Line of Symmetry is a line that can split a shape or object directly in half, leaving 2 identical sides. The 1st line of symmetry would be through the center of the middle-most triangle, the 2nd would be through the left corner of the middle-most triangle, and the final line of symmetry would be through the right corner of the middle-most triangle.
Here is an image showing the 3 Lines of Symmetry (the 3 colored lines).
I hope this helps!
