Rhetorical questions are those that don't expect an answer, right? But my dictionary doesn't give any definition of the sort under "rhetorical"--what gives? How are rhetorical questions related to rhetoric?
I seriously contemplated that word and definition when I was writing a dictionary. If someone asks you, "Is that a rhetorical question?" This implies that the one who posed the original statement didn't do a good job in their delivery.
The definition of 'rhetorical' is, basically, the art of speaking/writing effectively/persuasively. That implies that if someone posed a question persuasively there must be no room for an answer.
The art of rhetoric is that the sentence becomes a statement with a question mark. If artfully created...no one would respond with an answer.