Right-angled trigonometry, Pythagoras in 3D, and the area of a triangle (½ab sin C and Heron's rule)

What this note covers

1. Label a right triangle from the chosen angle
2. Find angles and use calculator mode correctly
3. Apply Pythagoras in two and three dimensions
4. Use one-half ab sin C for triangle area
5. Use Heron’s rule when three sides are known
6. Plan and verify a multi-step geometry solution

6 sections · 10 key terms & formulas · 6 common mistakes