Astatement that is true both forwards and backwards is called a

The answer is biconditional statement.

A biconditional statement is a statement that can be rewritten as a conditional or a converse. It is deemed true if the conditional and the converse statement is true. You can tell whether the statement is biconditional with the words, "if and only if."

Here is an example:

A polygon is a quadrilateral if and only if it has four sides.

A polygon has four sides, if and only if, it is a quadrilateral.

Since both statements are true, then this is a true biconditional statement.