Sin(120°) = √3/2
Sine — the y-coordinate of the corresponding unit-circle point, or opposite/hypotenuse in a right triangle.
How to derive sin(120°)
120° is in quadrant II (sine positive). Reference angle = 180° − 120° = 60°, so sin(120°) = +sin(60°) = √3/2.
Unit-circle context
The angle 120° corresponds to 2π/3 radians and sits Quadrant II on the unit circle.
Its reference angle is 60°, which is why sin(120°) shares its absolute value with sin(60°).
Other trig values at 120°
Related sin values
Frequently asked
- What is the exact value of sin(120°)?
- The exact value is √3/2. Its decimal approximation is 0.86603.
- How do you derive sin(120°)?
- 120° is in quadrant II (sine positive). Reference angle = 180° − 120° = 60°, so sin(120°) = +sin(60°) = √3/2.
- What is 120° in radians?
- 120° equals 2π/3 radians (multiply degrees by π/180).
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