Answer: Think of it this way, symmetry is basically a mirror and you can better find the perimeter because you'll know that the sides are the same length
Step-by-step explanation:
Well if you have two sides that are symmetrical or an entire shape is symmetrical you can find the perimeter easier. So let's say two lines are symmetrical and one has the length of 2 the other one can also be two. If we have a symmetrical shape, then is would be a complete reflection.
