What Is Sine?
In a right-angled triangle, the sine of an acute angle is the ratio of the length of the opposite side to the hypotenuse.
Examples of Sine
1
sin 30° = 1/22
sin 90° = 13
If opposite = 3 and hypotenuse = 5, sin θ = 3/5Formula and Key Points
Formula / rule
sin θ = opposite / hypotenuse
- Sine is a trigonometric ratio.
- For a right triangle, use the opposite side and hypotenuse.
- On the unit circle, sine is the y-coordinate.
- Sine values range from -1 to 1.
Why This Matters in Computer Science
Used in graphics, games, robotics, computer vision, spatial algorithms and coordinate calculations.
Worked Example
Problem
A right triangle has opposite side 6 and hypotenuse 10. Find sin θ.
- Use sin θ = opposite / hypotenuse.
- Substitute 6 / 10.
- Simplify the fraction to 3 / 5.
- Convert to decimal if needed: 0.6.
✓
Try Your Own Problem in Math Solver →
Final Answersin θ = 0.6
Sine, Cosine and Tangent
| Ratio | Formula in a right triangle |
|---|---|
| Sine | Opposite / Hypotenuse |
| Cosine | Adjacent / Hypotenuse |
| Tangent | Opposite / Adjacent |
Related Math Terms
Sine: Frequently Asked Questions
What is sine in a right triangle?
Sine is opposite divided by hypotenuse.
What is sin 30 degrees?
1/2 or 0.5.
Can sine be negative?
Yes. On the unit circle, sine ranges from -1 to 1.