Shinshia, this is the solution:
Radius of a circle = 19 m
Arc of Length = 16 m
In consequence, we have:
Arc Length = Central angle/360 * Circumference
Replacing by the values we know:
16 = Central angle/360 * 2 * π * r
16 = Central angle/360 * 38π
360 * 16 = Central angle * 38π
5,760 = Central angle * 38π
Central angle = 5,760/38π
Central angle = 48.25 degrees
Converting to radians, we have:
48.25 * π/180
0.8421
0.8 radians (rounding to the nearest tenth)