How to find the arc length of a circle

Increasingly in everyday practice necessary to solve the problem that once the seeds flipped on the mathematics lessons, but over the years, something forgotten. Find the length of the arc of a circle is one of the tasks with which a person can face in life.

You will need

• calculator, the value of the number π = 3,14 , the value of the radius r and Central angle α taken from the conditions of the problem.

Instruction

1. First you need to decide the main concepts. A circle is the set of all points plane that are at a given positive distance from some given point of the plane, called the center of the circle (point O). Arc - part of circumference islocated between two points A and b of this circle, where OA and OV radii of this circle. To distinguish between these arcs, each of them mark an intermediate point L and M. Thus, we obtain two arcs ALB and AMB.
2. The arc of the circle determined by a Central angle ?. Angle with vertex in the center of the circle is called its Central angle. If the Central angle is less than straight angle, then its degree measure is equal
   ?, and if more straight angle, 360° - ?.
   
3. So, the arc of the circle defined by the radius of the circle r and Central angle ?. Knowing these two values, it is easy to calculate the length of the arc L by the formula:
   L = ?r?/180
   where ? is a numeric constant equal 3,14.
   Substituting in the formula values ?, r ? and using a calculator you can easily calculate the length of the arc L.