<p>Definitely know sohcahtoa. It's not even so much a formula as the definition (well, one possible definition out of at least three) of the trig functions.</p>
<p>I'd also suggest knowing at least two, preferably three, ways to find the area of a triangle. They save you quite a bit of time. Which three? You pick. There are many, some common, some incredibly obscure.</p>
<p>Note however that trig is not required for the SAT (unlike the ACT, where you will get about 4 basic trig questions). The "special right triangles" given on the SAT are all you need as far as "trig" questions go. If you haven't had trigonometry before taking the SAT it probably doesn't make sense to try to learn it just for the test.</p>
<p>whom u r waiting 4</p>
<p>You can check out the [ACT</a> Math Formula Sheet](<a href=“http://www.ACTMathFormulas.com%5DACT”>http://www.ACTMathFormulas.com). That cheat sheet has everything!</p>
<p>Or you can google “act math formulas” for free versions (though, admittedly, not laminated 
)</p>