If A is a subset of C and B is also a subset of C, then is A union B a subset of C also (subset, not a proper subset)? Intuitively, I'd say no, but I could be wrong..?

Question

anonymous · Answer

Wait, I think I'm starting to think otherwise. But okay, I'll wait for your reply.

anonymous · Answer

Haha I think I got it. But okay, I'll still wait for your reply just to confirm.

anonymous · Answer

|dw:1340779359345:dw|
As you see, A and B are subsets of C. 
Their union is the "shaded area".
|dw:1340779385082:dw|
So yes, their union is still a subset of C! All points belong within it.