They are quite probably boundaries of some kind. Check the legend on the map to find out what kind of boundary they are.
Usually they indicate the borders between the states.
because their black line help them to wriggle
boarders
In typesetting the space between lines is called lead or leading. The space between letters is keening.
Some states do not have earthquakes because they are not located on or near fault lines.
In most cases the black lines which are between the states point out the border between different states, telling the map reader when the you are in a different state.
Usually they indicate the borders between the states.
On maps, black lines between states represent boundaries or borders, where one state stops and the others starts. These are also called state lines.
State boarder
State boarder
on a map,what do black lines between states usually represent? state boundries
I think you're talking about the borders of the states. Sometimes, between countries, if normal borders are solid lines and you see dotted lines in some places, you can see in the map key that the dots might mean a disputed border (like currently for Somalia).
usually it's state boundaries
By dashes.
Having two dashes on a triangle is common notation in arithmetic, specifically geometry. Two dashes mean that there is one dash each on two different lines of the triangle, and this indicates that the two lines are of equal length. This also means that the triangle is an isosceles triangle.
interstate
Depending on the type of map you are referring to, the solid black line could indicate a national boundary. If it is a map of states, it could be a state boundary.