You can put this solution on YOUR website! Equilaterial:
Every equilateral triangle has three lines of symmetry. These are the bisectors of the angles/sides. If you actually cut a triangle out of paper and fold it it is much easier to see. But one is the axis of symmetry (down the middle) and the other two cross through the center. These are examples of bilateral symmetry . (two sides that are mirror images of each other)
Isosceles:
Each one is different but most also have the main axis of symmetry from the top peak to the bottom middle.
Hope I helped :)