It is a way to find missing sides in a right triangle. Try to remember SOH CAH TOH which is all of the equations you could need.
SOH would be the equation Sin(angle)=Opposite/hypotenuse
CAH would be the equation Cos(angle)=adjacent/hypotenuse
TOA would be the equation Tan(angle)=opposite/adjacent
The adjacent side always touches the right angle and missing or given angle which is called feta.
The hypotenuse side only touches feta.
The opposite side only touches the right angle.
Hope that helps
