Pythagoras' Theorem Note: Don't forget to square-root! Sin, Cos, Tan Notes: 1. Ways to remember: SOH-CAH-TOA Silly Old Horses Chase After Hens That Offer Advice Formula Triangles 2. Sin, Cos and Tan are always with an angle. 3. If you're looking for an angle you need to use the inverses - sin-1, cos-1, tan-1,