Geometry Regents Exam Prep - Practice Test & Study Guide for NY Regents

To determine the length of an arc in a circle, you can use the formula that incorporates the central angle measured in degrees. The arc length is calculated by the proportion of the angle to the full circle, which is 360 degrees. Therefore, the formula is given as:

Arc length = (θ/360) * 2πr

In this formula, θ represents the angle in degrees, r is the radius of the circle, and 2πr is the total circumference of the circle. By multiplying the fraction of the circle represented by the angle (θ/360) by the full circumference, you obtain the precise length of the arc corresponding to that angle.

The other options do not represent the correct formula for arc length. For instance, while one option suggests a direct relationship between radius and angle without considering the circle's entire circumference, another option gives the formula for the circumference of the circle, and yet another represents the area of the circle. All of these do not directly relate to finding the length of a specific arc based on an angle.