Tan(120°) = -√3
Tangent — sine divided by cosine, equivalently opposite/adjacent in a right triangle; undefined where cos = 0.
How to derive tan(120°)
120° is in quadrant II (tangent negative). Reference angle = 60°, so tan(120°) = −tan(60°) = −√3.
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 tan(120°) shares its absolute value with tan(60°).
Other trig values at 120°
Related tan values
Frequently asked
- What is the exact value of tan(120°)?
- The exact value is -√3. Its decimal approximation is -1.73205.
- How do you derive tan(120°)?
- 120° is in quadrant II (tangent negative). Reference angle = 60°, so tan(120°) = −tan(60°) = −√3.
- What is 120° in radians?
- 120° equals 2π/3 radians (multiply degrees by π/180).
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