Explanation

Trigonometry studies relationships between angles and sides of a triangle, usually a right triangle.

Key ratios for a right triangle:

1. Sine (sin) = opposite / hypotenuse

2. Cosine (cos) = adjacent / hypotenuse

3. Tangent (tan) = opposite / adjacent

Other ratios (reciprocals):

• Cosecant (csc) = 1 / sin

• Secant (sec) = 1 / cos

• Cotangent (cot) = 1 / tan

Example:
Right triangle with angle θ: opposite = 3, adjacent = 4, hypotenuse = 5

• sin θ = 3/5

• cos θ = 4/5

• tan θ = 3/4