Definition of Trigonometric Ratios - JSS3 Mathematics Lesson Note

Trigonometric ratios are mathematical relationships between the sides of a right triangle. The main ratios are:

Sine (sin): Ratio of the length of the opposite side to the length of the hypotenuse.

Cosine (cos): Ratio of the length of the adjacent side to the length of the hypotenuse.

Tangent (tan): Ratio of the length of the opposite side to the length of the adjacent side.

For a right triangle with angle θ:

sin(θ) = opposite / hypotenuse

cos(θ) = adjacent / hypotenuse

tan(θ) = opposite / adjacent

These ratios help in calculating unknown angles or sides of a triangle when given certain measurements.