Key learning points

1. There are specific ratios within the two key right-angled triangles defined by the unit circle.
2. The first right-angled triangle has hypotenuse of length one.
3. The opposite and adjacent sides of this triangle have lengths sin⁡(θ) and cos⁡(θ), respectively.
4. The second right-angled triangle has an adjacent side length of one.
5. The opposite side of this triangle has length tan⁡(θ)

Common misconception

Keywords

• Trigonometric ratios - The trigonometric ratios are ratios between each pair of lengths in a right-angled triangle.

• Opposite - The opposite side of a right-angled triangle is the side which is opposite the marked angle.

• Adjacent - The adjacent side of a right-angled triangle is the side which is next to both the right angle and the marked angle.