Answer:

Step-by-step explanation:

Given that A is subset of B

⇒ A ⊆ B  ........(1)

Also, Given that B is subset of C

⇒ B ⊆ C  .......(2)

And C is subset of A

⇒ C ⊆ A .......(3)

Now, from equation (1) and equation (2)

We have, A ⊆ C .......(4)

So, from equation (3) and equation (4)

C ⊆ A and A ⊆ C

⇒ A = C

Hence proved.