Hello!
For #1, the shape is not symmetrical because when folded on the line, the top of the shape does not match the bottom of the shape.
For #2, the shape is symmetrical because both sides of the shape match each other when they are folded.
For #3, the shape is symmetrical as well because like w/ #2, both sides of the shape are equal to each other when folded.
Lastly, for #4, the shape is not symmetrical because even though both sides of the shape are similar, they are not equivalent to each other when folded, making this shape not symmetrical.
I hope this helps you out!