There's a certain amount of memorization that should be done for the math portion of the SAT. Relying on just the formulas given on the test is not enough (those are just a small, incomplete subset of what you need to know, and you shouldn't need to refer to them while taking the test as you should have them memorized). It's possible to get away with a lot using your calculator, but it's better not to.

In school, you should have learned perfect squares up to at least 15^2 or 16^2. These are also the ones you should know for the SAT. The more you know, the better. If you don't know these perfect squares now, take the time to memorize the ones you don't know so well. (At the least, know how to generate a short list of them on your calculator very quickly--but memorization is the better choice.)

Here's a list up to 20^2.

1^2 = 1

2^2 = 4

3^2 = 9

4^2 = 16

5^2 = 25

6^2 = 36

7^2 = 49

8^2 = 64

9^2 = 81

10^2 = 100

11^2 = 121

12^2 = 144

13^2 = 169

14^2 = 196

15^2 = 225

16^2 = 256

17^2 = 289

18^2 = 324

19^2 = 361

20^2 = 400

There are many tricks and patterns with perfect squares, but I'll leave that for another time.