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    Sin 20 Degrees

    Sin, Cos, Tan, Cot of an Angle
    Function
    Angle (°)

    What is sin 20°?

    Answer

    sin 20° ≈
    0.3420

    Angle in radians: 20° = π/9. The point of the angle is in quadrant I, where sine is positive.

    ≈ — rounded to 4 decimal places. sin 20° can't be written with square roots: 20° is not a multiple of 3°.

    P(cos 20°, sin 20°) ≈ (0.9397, 0.3420)

    xyOP

    P(cos 20°, sin 20°) ≈ (0.9397, 0.3420)

    Highlighted: the projection on the y-axis — sine, y ≈ 0.3420.

    All four functions of 20°
    FunctionExact valueDecimal
    sin 20°—≈ 0.3420
    cos 20°—≈ 0.9397
    tan 20°—≈ 0.3640
    cot 20°—≈ 2.7475

    See Also

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    https://calculat.io/en/number/trigonometry/sin--20Copy
    <a href="https://calculat.io/en/number/trigonometry/sin--20">Sin 20 Degrees: Sine of 20° on the Unit Circle - Calculatio</a>Copy
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    Sin 20 Degrees: Sine of 20° on the Unit Circle. sin 20° ≈ 0.3420. The sine is the y-coordinate of the point at 20° on the unit circle.
    https://calculat.io/en/number/trigonometry/sin--20/generated.jpgCopy

    Sine of nearby angles

    Anglesin
    17°≈ 0.2924
    18°(√5 − 1)/4
    19°≈ 0.3256
    20°≈ 0.3420
    21°≈ 0.3584
    22°≈ 0.3746
    23°≈ 0.3907
    Recalculate with different values ↑

    FAQ

    What is sin 20°?

    sin 20° ≈ 0.3420

    Why does sin 20° have no exact value?

    A trigonometric value of a whole number of degrees can be written with square roots only when the angle is a multiple of 3°. 20° is not, so no such exact form exists; the value is used as a decimal: sin 20° ≈ 0.3420.

    Why does a calculator show 0.9129 for sin 20?

    The calculator is in radian mode (RAD): it takes sin 20 as the sine of 20 radians, sin 20 rad ≈ 0.9129. Switch it to degrees (DEG): sin 20° ≈ 0.3420. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

    See Also