Sin 31 Degrees

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

What is sin 31°?

Answer

sin 31° ≈
0.5150

Angle in radians: 31° = 31π/180. The point of the angle is in quadrant I, where sine is positive.

≈ — rounded to 4 decimal places. sin 31° can't be written with square roots: 31° is not a multiple of 3°.

P(cos 31°, sin 31°) ≈ (0.8572, 0.5150)

xyOP

P(cos 31°, sin 31°) ≈ (0.8572, 0.5150)

Highlighted: the projection on the y-axis — sine, y ≈ 0.5150.

All four functions of 31°
FunctionExact valueDecimal
sin 31°—≈ 0.5150
cos 31°—≈ 0.8572
tan 31°—≈ 0.6009
cot 31°—≈ 1.6643

See Also

Recalculate with different values ↑

Sine of nearby angles

Anglesin
28°≈ 0.4695
29°≈ 0.4848
30°1/2
31°≈ 0.5150
32°≈ 0.5299
33°≈ 0.5446
34°≈ 0.5592

FAQ

What is sin 31°?

sin 31° ≈ 0.5150

Why does sin 31° 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°. 31° is not, so no such exact form exists; the value is used as a decimal: sin 31° ≈ 0.5150.

Why does a calculator show −0.4040 for sin 31?

The calculator is in radian mode (RAD): it takes sin 31 as the sine of 31 radians, sin 31 rad ≈ −0.4040. Switch it to degrees (DEG): sin 31° ≈ 0.5150. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

See Also