Arc of a Circle: Definition, Properties, and Examples

Arc of a Circle

A fundamental concept in geometry, the arc of a circle is applied in many disciplines, including engineering, architecture, and even the arts. This blog will explore the meaning of an arc, its characteristics, and offer real-world examples to highlight its uses.

What is an Arc?

A segment of a circle's circumference is called an arc. It can be conceptualized as the "curve" that lies between the two points on the circle that define it.

Arc Types

Arcs are typically divided into two categories:
  • Minor Arc: A minor arc is one that makes up less than half of the circle's circumference. It is the circle's shortest route between two locations.
  • Major Arc: An arc that is more than half of the circumference of the circle. It is the longer path between two points on the circle.

Naming an Arc

Arcs are named based on their endpoints. For instance, if the endpoints of an arc are A and B, the arc can be denoted as . If it's necessary to distinguish between a minor and a major arc with the same endpoints, an additional point on the arc is often included. For example, if point C lies on the arc between A and B, the arc can be denoted as

Properties of an Arc

  • Central Angle: The central angle is the angle that an arc at the circle's center subtends. This angle is less than 180 degrees for a minor arc and more than 180 degrees for a major arc.
  • Arc Length: The length of an arc can be calculated using the formula: 
    Arc Length=×2πr.
  • Chord: A chord is a line segment whose endpoints lie on the circle. The arc corresponding to a chord is the portion of the circle between the chord's endpoints.

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 Practical Applications of Arcs

Building and Design

Fundamental components of many architectural structures' designs and constructions are arcs. They are used for structural and functional objectives in addition to aesthetic ones.

  • Arches Bridges: Arched bridges distribute weight and offer structural stability by utilizing the characteristics of arcs. These bridges are robust and long-lasting because to the way in which the shape efficiently converts the force of gravity into compressive stress.
  • Windows and Doorways: Because of their durability and classic aesthetic appeal, arched windows and doorways are frequently found in architecture. By dispersing weight away from the aperture, the arc shape preserves structural integrity while permitting greater spans.
  • Engineering:In mechanical and civil engineering, where they are utilized in the design of numerous parts and systems, arcs are essential.

Cams and Gears

  • Gears: To guarantee a smooth and effective transfer of rotational motion and force, arc segments are frequently used in the construction of gear teeth. For this, the involute gear profile—which has arc segments—is frequently employed.
  • Cams: In cam mechanisms, rotating motion is converted to linear motion by designing the cam profile utilizing arcs. perfect timing and movement in machines are guaranteed by the arc's perfect curvature.


  • Pipelines: Arcs are utilized in the construction of curved pipeline sections to facilitate seamless direction changes without putting undue strain on the pipes.

Art and Design

Arcs are widely used in art and design due to their aesthetic appeal and ability to create dynamic and harmonious compositions.

Graphic Design

  • Logos and Icons: Many logos and icons incorporate arcs to create visually appealing shapes and symbols. The use of arcs can convey movement, fluidity, and modernity.
  • User Interface Design: Arcs are used in user interface design to create buttons, progress indicators, and other elements that are both functional and aesthetically pleasing.

Furniture and Interior Design

  • Curved Furniture: Arcs are used in the design of furniture to create elegant and comfortable shapes. Curved lines in chairs, tables, and other pieces add a touch of sophistication and uniqueness to interior spaces.
  • Transportation

In the transportation sector, arcs play a crucial role in the design of roads, railways, and tracks.

Road Design

  • Curved Roads: Arcs are used to design curves in roads, ensuring safe and smooth transitions for vehicles. The radius of the arc determines the sharpness of the curve, which is critical for maintaining safety and comfort at various speeds.
  • Ramps and Overpasses: The curvature in ramps and overpasses is designed using arcs to facilitate smooth and safe transitions between different elevations and directions.

Railway Tracks

  • Curved Tracks: Railway tracks are designed with arcs to enable trains to navigate turns smoothly. The curvature must be carefully calculated to maintain stability and safety at varying speeds.

Comprehending the notion of arcs and their characteristics is crucial for resolving several geometric issues and for utilizing them in diverse domains. Understanding an arc's definition, kinds, characteristics, and length will help you better understand the functions that arcs perform in both theoretical and real-world settings. Whether you're a professional, a student, or just interested in geometry, understanding the idea of arcs can definitely improve your toolset for mathematical problems.

FAQs: (Frequently Asked Questions)

Q1: What is an Arc of a Circle?

Ans: An arc is a part of the circumference of a circle. It is defined by two points on the circle and the continuous curve between them. Arcs can be classified into two main types

  • minor Arc: An arc that is smaller than a semicircle.
  • Major Arc: An arc that is larger than a semicircle.

Q2: How is an Arc Represented?

Ans: An arc is typically denoted by the symbol "⌒" over the endpoints of the arc. For example, the arc between points A and B on a circle is represented as ⌒AB.

Q3: What are the Properties of an Arc?

Ans: Key properties of an arc include:

  • Central Angle: The angle subtended by the arc at the center of the circle.
  • Arc Length: The distance along the curved line forming the arc.
  • Chord: The straight line connecting the endpoints of the arc.
  • Sector: The region bounded by two radii and the arc.

Q4: What is a Semicircular Arc?

Ans: A semicircular arc is half of the circle, with its endpoints lying on the diameter. It subtends a central angle of 180° and represents half the circumference of the circle.

Q5: How to Distinguish Between a Minor and a Major Arc?

Ans: To distinguish between a minor and a major arc:

  • A Minor Arc is less than 180°.
  • A Major Arc is more than 180°.

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