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Length Of An Arc

The length of an arc is the linear distance along the curved boundary of a portion of a circle. It represents a fraction of the circle's total circumference, determined by the central angle subtended by the arc at the center of the circle.

Key Concepts

An arc is a continuous part of the circumference of a circle.

The length of an arc is directly proportional to the central angle it creates at the center of the circle.

To calculate the arc length, you find the fraction of the circle represented by the central angle and multiply it by the total circumference.

Formula & Equation

l = \frac{\theta}{360^\circ} \times 2\pi r

l = length of the arc, \theta = central angle subtended by the arc in degrees, r = radius of the circle, \pi = mathematical constant (approximately \frac{22}{7} or 3.14)

Common Misconceptions

Myth: Students often confuse the length of an arc with the area of a sector.

Fact: The length of an arc measures the one-dimensional distance along the curved boundary, whereas the area of a sector measures the two-dimensional space enclosed by the arc and two radii.

Real World Applications

The curved outer edge of a pizza slice represents an arc, and its length depends on the angle at which the slice is cut.

The path traced by the tip of a car's windshield wiper as it moves back and forth forms the length of an arc.

Frequently Asked Questions

How do you calculate the length of an arc?

You calculate it by dividing the central angle by 360 degrees, then multiplying that fraction by the total circumference of the circle.

What is the difference between a minor arc and a major arc?

A minor arc has a central angle of less than 180 degrees, making it shorter than a semicircle, while a major arc has an angle greater than 180 degrees.

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