Trigonometry basics

Story hook

A person stands 50 m from a tall building. The angle from his eyes to the top of the building is 60°. How tall is the building?

The tan trick: tan(60°) = height / 50. tan(60°) = √3 ≈ 1.732. Height = 50 × 1.732 = 86.6 m.

In 15 seconds, you've solved a Class 10 trigonometry problem.

Trigonometry on CSAT is rare but easy. Just 6 formulas, 1 table to memorise, and 80% of "heights and distances" problems become 30-second affairs.

Why this matters for UPSC

For CSAT (Paper II, qualifying 33%):

• 1-3 questions per paper are trigonometry. Heights & distances + basic identities.
• GS-I Geography: Cartography uses trig (latitude-longitude calculations).
• GS-III Science: Optics, surveying, navigation.

Modest weight in CSAT, but each question is fast if you know the table. 30 minutes of memorisation = ~3-5% of marks.