Sin 100 Degrees

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

What is sin 100°?

Answer

sin 100° ≈
0.9848

Angle in radians: 100° = 5π/9. The point of the angle is in quadrant II, where sine is positive.

≈ — rounded to 4 decimal places. sin 100° can't be written with square roots: 100° is not a multiple of 3°.

sin 100° = sin(180° − 80°) = sin 80° ≈ 0.9848

P(cos 100°, sin 100°) ≈ (−0.1736, 0.9848)

xyOP

P(cos 100°, sin 100°) ≈ (−0.1736, 0.9848)

Highlighted: the projection on the y-axis — sine, y ≈ 0.9848.

All four functions of 100°
FunctionExact valueDecimal
sin 100°—≈ 0.9848
cos 100°—≈ −0.1736
tan 100°—≈ −5.6713
cot 100°—≈ −0.1763

Reference angle: sin 80° ≈ 0.9848

See Also

Recalculate with different values ↑

Sine of nearby angles

Anglesin
90°1
97°≈ 0.9925
98°≈ 0.9903
100°≈ 0.9848
101°≈ 0.9816
105°(√6 + √2)/4
106°≈ 0.9613

FAQ

What is sin 100°?

sin 100° ≈ 0.9848

Why does sin 100° 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°. 100° is not, so no such exact form exists; the value is used as a decimal: sin 100° ≈ 0.9848.

Why does a calculator show −0.5064 for sin 100?

The calculator is in radian mode (RAD): it takes sin 100 as the sine of 100 radians, sin 100 rad ≈ −0.5064. Switch it to degrees (DEG): sin 100° ≈ 0.9848. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

See Also