# I Is angle a vector or a scalar quantity?

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1. Oct 27, 2016

### Yatin

Is angle a vector or a scalar quantity?
(eg- θ in l=rθ)

2. Oct 27, 2016

### PeroK

An angle itself is a scalar, but a rotation is a vector.

The angle $\pi/4$ has no implied direction as an angle. But, you can have a rotation of $\pi/4$ in any direction.

3. Oct 28, 2016

### David Lewis

Rotation (angular displacement) has a uniquely-defined magnitude and direction, but is not a vector quantity because it doesn't obey the commutative law of vector addition (the result of two rotations in 3 dimensions depends on the order in which you perform them).