For anyone that can offer help, I mapped mine out by starting with the first 2 premises:

AB = CT, AB = SA, so CT = SA.

The conclusion shows that /SA = /CT, which is the opposite of what is above, so that checked out.

I was wondering if that thought process above is correct? Also, my issue is that I can only answer these questions correctly if I write out a diagram on paper. Is this something I should be worried about?

Got the three questions with higher difficulty correct, but the two questions with lower difficulty incorrect... any tips on what I might be doing wrong? 😭