Three-year-old megan encounters a swinging chair that is hung from the ceiling by a hook. once she is told what it is, she incorporates the new chair into her existing "chair schema." according to piaget's theory, this is called

assimilation  

Explanation:

Assimilation: In psychology, the term assimilation was proposed by Jean Piaget in his theory of cognitive development and is defined as a cognitive process that directs the way an individual incorporates a particular new information into pre-existing information or knowledge. The process of assimilation involves the procedure of learning and comprehension.

Example: To analyze a particular object and then knowing its history to writes or learn something about that object.

In the question above, according to Piaget's theory, the given statement is called assimilation.