Sine: Opposite edge/hypotenuse. Remember: sinA=a/c=a/h is used to representing the hypotenuse with C.

Cosine: adjacent side/hypotenuse. Note: COSA = B/C = A/H.

Tangent: Opposite/adjacent edges. Note: tanA=a/b

Cotangent: adjacent edge/opposite edge. Note: cotA=b/a

The tangent and cotangent of the same angle are a pair of opposite numbers.