$\"\"$

Definition of radian measure :

If a central angle $\"\"$ , in a circle of radius $\"\"$ , cuts off an arc of length $\"\"$ , then the measure of $\"\"$ , in radians is $\"\"$ .

$\"\"$

Find $\"\"$ .

Consider $\"\"$ .

Substitute the values of $\"\"$ and $\"\"$ in above formula.

$\"\"$

Thus, the radian measure of $\"\"$ is 0.5. $\"\"$

The angle $\"\"$ rad.