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High SchoolGeometry
Trigonometry
Sin, Cos, Tan and the Pythagorean Theorem
Use trigonometric ratios to find missing sides and angles in right-angled triangles.
✓ SOH: Sin = Opposite/Hypotenuse✓ CAH: Cos = Adjacent/Hypotenuse✓ TOA: Tan = Opposite/Adjacent
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📖 Understanding Trigonometry
Trigonometry studies relationships between angles and sides in triangles. In a right-angled triangle, we label sides relative to the angle θ: Opposite (across from θ), Adjacent (next to θ), Hypotenuse (longest side, opposite right angle).
The three main ratios: Sin θ = Opposite/Hypotenuse, Cos θ = Adjacent/Hypotenuse, Tan θ = Opposite/Adjacent. Remember: SOH CAH TOA.
Pythagoras' Theorem: In a right triangle, a² + b² = c² where c is the hypotenuse. Use this to find a missing side when you know two sides.
To find an angle, use inverse functions: θ = sin⁻¹(O/H), θ = cos⁻¹(A/H), θ = tan⁻¹(O/A).
🔑 Key Points to Remember
- ✓SOH: Sin = Opposite/Hypotenuse
- ✓CAH: Cos = Adjacent/Hypotenuse
- ✓TOA: Tan = Opposite/Adjacent
- ✓Pythagoras: a² + b² = c²
- ✓Use inverse trig to find angles
#trigonometry#sin#cos#tan#pythagoras#high school
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