Consider the following premises. If Robert were an astronaut, then it is windy. If it is windy, then Robert is an astronaut. If Robert were an astronaut, then it is windy. Can we infer the following from them? If we can, name the inference rule being used: Robert is an astronaut if and only if it is windy.
We can infer this via the biconditional introduction rule. Therefore, the answer is yes.