Final answer:
Dorothy Vaughan must learn the secret handshake to join the club, and as of now, she is not a member because she hasn't learned it yet. No information is provided on when or how she will learn the handshake or join the club.
Step-by-step explanation:
Remember, participating in club activities often involves meeting certain criteria or requirements, which, in this case, is learning a secret handshake.
In order for Dorothy Vaughan to join the club, she must learn the secret handshake. Once she learns it, she will be eligible to join the club.
Dorothy Vaughan is not in the club because she has not learned the secret handshake yet. Once she learns it, she will be able to join.
The question does not provide information about when Dorothy Vaughan learned the secret handshake.
There is no information provided on how Dorothy Vaughan joined the club. However, it can be inferred that once she learned the secret handshake, she would be able to join.