Introduction to Trigonometry

Learn the basics of trigonometry: sine, cosine, tangent, and how to use them in right triangles.

8th Grade

Trigonometry

~45 min

🎮 Interactive Activity: Trigonometric Ratio Calculator

Calculate sin, cos, and tan for different angles!

Angle: 30°

🎮 Interactive Activity: SOH CAH TOA Helper

Use SOH CAH TOA to find trigonometric ratios!

Opposite: 3, Adjacent: 4, Hypotenuse: 5.0

1. What is Trigonometry?

📚 Trigonometry Definition

Trigonometry is the study of relationships between angles and sides in triangles, especially right triangles.

Three Basic Ratios:

• Sine (sin): opposite / hypotenuse

• Cosine (cos): adjacent / hypotenuse

• Tangent (tan): opposite / adjacent

2. Trigonometric Ratios

3. SOH CAH TOA Mnemonic

4. Special Angles

5. Finding Missing Sides

6. Real-World Applications

7. Worked Examples

8. Frequently Asked Questions

Practice Time!

Practice Quiz

Questions

Correct

Score

What does SOH CAH TOA stand for?

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In a right triangle, if opposite = 3 and hypotenuse = 5, what is sin(θ)?

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What is cos(0°)?

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What is sin(90°)?

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If tan(θ) = 1, what is the angle θ?

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In a right triangle with angle 30°, if the opposite side is 5, what is the hypotenuse?

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What is the value of sin(30°)?

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If cos(θ) = 0.6 and hypotenuse = 10, what is the adjacent side?

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What is tan(60°)?

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Which trigonometric ratio uses opposite and adjacent sides?

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