Class 10 · Chapter 8 · Trigonometry

Introduction to Trigonometry

Ratios of the sides of a right triangle, named from the angle you stand at.

Source: NCERT Mathematics, Class 10

1. 8.1Opposite, Adjacent, HypotenuseAttention · Look at the angle first, then name the sides from it.8 min
2. 8.2Ratios of 30°, 45° and 60°Attention · Look at the half-triangle: the short side is opposite 30°.10 min
3. 8.3sin²A + cos²A = 1 Is PythagorasAttention · Look at where the identity comes from: Pythagoras.8 min
4. 8.4From One Ratio to All the OthersAttention · Look for the missing side first. Every other ratio is read from it.8 min