Sin 39 Degrees

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

What is sin 39°?

Answer

sin 39° ≈
0.6293

Angle in radians: 39° = 13π/60. The point of the angle is in quadrant I, where sine is positive.

≈ — rounded to 4 decimal places. An exact form of sin 39° in square roots exists, but it is unwieldy — nested radicals.

P(cos 39°, sin 39°) ≈ (0.7771, 0.6293)

xyOP

P(cos 39°, sin 39°) ≈ (0.7771, 0.6293)

Highlighted: the projection on the y-axis — sine, y ≈ 0.6293.

All four functions of 39°
FunctionExact valueDecimal
sin 39°—≈ 0.6293
cos 39°—≈ 0.7771
tan 39°—≈ 0.8098
cot 39°—≈ 1.2349

See Also

Recalculate with different values ↑

Sine of nearby angles

Anglesin
36°√(10 − 2√5)/4
37°≈ 0.6018
38°≈ 0.6157
39°≈ 0.6293
40°≈ 0.6428
41°≈ 0.6561
42°≈ 0.6691

FAQ

What is sin 39°?

sin 39° ≈ 0.6293

Is there an exact value of sin 39°?

Yes: 39° is a multiple of 3°, and the values of such angles can be written with square roots — but the expression is unwieldy, with nested radicals built from the values of 18° and 15° (3° = 18° − 15°). In practice the decimal is used: sin 39° ≈ 0.6293.

Why does a calculator show 0.9638 for sin 39?

The calculator is in radian mode (RAD): it takes sin 39 as the sine of 39 radians, sin 39 rad ≈ 0.9638. Switch it to degrees (DEG): sin 39° ≈ 0.6293. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

See Also