The ratio of the arc length to the radius?

Answer 1

The arc_length is given by the angle measured in radians times the radius of the arc.

To convert degrees to radians divide by 180° and multiply by π radians.

eg 45° = 45° ÷ 180° × π radians = π/4 radians.

eg 60° = 60° ÷ 180° × π radians = π/3 radians.

Answer 2

It is the angle, measured in radians, that the arc makes at the centre of the circle.

Answer 3

the arc length is equal to the radius times the angle subtended in radians.For examale the arc length of a semicircle (angle 180 degrees = pi) is radius x pi