sin θ = opposite / hypotenuse

↳opp=3, hyp=5 → sin θ = 3/5

cos θ = adjacent / hypotenuse

↳adj=4, hyp=5 → cos θ = 4/5

tan θ = opposite / adjacent

↳sin/cos: tan 45° = 1

sin² θ + cos² θ = 1

↳sin²30 + cos²30 = 1/4 + 3/4 = 1

sin 30° = 1/2; cos 30° = √3/2; tan 45° = 1

↳1/2; cos 30° = √3/2