Sine (sin)
Cosine (cos)
Tangent (tan)
θ = theta
sin θ = opposite/hypotenuse
cos θ = adjacent/hypotenuse
tan θ = opposite/adjacent
Other
Opposite is the side opposite to theta or the angle you need
to know
Hypotenuse is the side opposite the right angle, or the
longest side
Adjacent is the side next to theta that is not opposite the
right angle
Practice/Notes (assume all triangles are right triangles)
Given triangle DEF, Prove a2 + b2 = c2
(b/c)2 + (a/c) 2 = 1
b2/c2 + a2/c2 = 1
a2 + b2 = c2