Is Transitivity Applicable in Proving Subset Relations Among Sets A, B, and C?

[adriang]

Hello I'm having problems with actually proving this with some mathematics.
Let A, B, C be sets. Prove that if A is a subset of B and B is a subset of C then A is a subset of C.
Thanks.

 

[tiny-tim]

hi adriang!

always start proofs of this sort with "if a is in A, …"

 

[madsmh]

$$A \subseteq B$$ means if $$x\in A$$ then $$x\in B$$ for all $$x\in A$$.