Sine and cosine of complementary angles

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Other lessons in this sub-strand

1. The three ratios
2. Finding angles, elevation and depression
3. Labelling from either acute angle
4. Calculators and mathematical tables
5. When the unknown is the denominator
6. Sine and cosine of complementary angles
7. Relating sine, cosine and tangent
8. Special angle 45 degrees
9. Special angles 30 and 60 degrees
10. Special angle 90 degrees and the exact-value table
11. Inverse ratios in practice
12. Solving a complete right-angled triangle
13. Height from two positions
14. Depression from a height
15. A clinometer and trigonometry around us