Chord Analysis Calculator






Chord Analysis Calculator – Geometry & Circle Segment Tool


Chord Analysis Calculator

A specialized chord analysis calculator designed for geometric precision. Calculate circle chord properties including length, sagitta, arc length, and central angle in real-time.


Enter the distance from the center to the edge.
Radius must be greater than 0.


The angle subtended by the chord at the center.
Angle must be between 0 and 360.


Chord Length: 10.00
Sagitta (h):
1.34
Arc Length (s):
10.47
Segment Area:
4.53

Formula used: Chord (c) = 2r · sin(θ/2). Results are based on Euclidean geometry.

Geometric Visualization

Dynamic diagram showing the chord (blue line) and the circle segment (shaded area).

Chord Property Reference Table


Property Value Metric

What is a Chord Analysis Calculator?

A chord analysis calculator is a precision geometric utility used to solve the complex relationships between circle components. In geometry, a chord is a straight line segment whose endpoints both lie on a circular arc. This chord analysis calculator processes inputs such as radius and central angle to provide instantaneous data on chord length, height (sagitta), and arc dimensions.

Engineers, architects, and students use the chord analysis calculator to determine structural requirements for curved designs. Common misconceptions include confusing the chord with the arc length or assuming the chord is simply the diameter. A chord can only be the diameter if it passes through the circle’s center point, representing the maximum possible chord length.

Chord Analysis Calculator Formula and Mathematical Explanation

The mathematics behind a chord analysis calculator relies heavily on trigonometry. Specifically, we use the properties of isosceles triangles formed by the radius and the chord. Below is the step-by-step derivation used in our chord analysis calculator.

1. Chord Length (c): Derived using the sine function: c = 2 × r × sin(θ/2).
2. Sagitta (h): The vertical distance from the center of the chord to the arc: h = r × (1 – cos(θ/2)).
3. Arc Length (s): Based on the angle in radians: s = r × (θ × π / 180).
4. Segment Area (A): The area between the chord and the arc: A = (r² / 2) × ((π × θ / 180) – sin(θ)).

Variables used in the Chord Analysis Calculator
Variable Meaning Unit Typical Range
r Circle Radius Units (m, ft, in) > 0
θ Central Angle Degrees 0 to 360
c Chord Length Units 0 to 2r
h Sagitta (Height) Units 0 to r

Practical Examples (Real-World Use Cases)

Example 1: Architectural Arch Design
A construction team needs to build a masonry arch with a radius of 15 feet and a central angle of 90 degrees. By using the chord analysis calculator, they find the chord length (the span of the arch) is 21.21 feet and the sagitta (the height of the curve) is 4.39 feet. This allows for precise material cutting.

Example 2: Mechanical Gear Manufacturing
In gear design, a technician needs to measure the distance between two teeth on a gear with a 100mm radius where the teeth are separated by a 10-degree angle. The chord analysis calculator determines a chord length of 17.43mm, ensuring the teeth mesh correctly with the mating gear.

How to Use This Chord Analysis Calculator

  1. Enter the Radius: Input the radius of your circle in the first field. This is the distance from the center to any point on the perimeter.
  2. Input the Central Angle: Enter the angle (in degrees) that the chord spans.
  3. Review Results: The chord analysis calculator updates automatically. Observe the “Chord Length” as the primary result.
  4. Analyze Secondary Values: Check the sagitta for height clearance and the segment area for surface calculations.
  5. Visualize: Look at the dynamic SVG diagram to ensure the geometric representation matches your expectations.

Key Factors That Affect Chord Analysis Calculator Results

  • Radius Magnitude: Larger radii proportionally increase chord and arc lengths for the same angle.
  • Angular Breadth: As the central angle approaches 180 degrees, the chord length approaches the diameter.
  • Unit Consistency: Ensure your radius is in the same unit you expect for your chord length result.
  • Precision of π: Our chord analysis calculator uses high-precision constants to ensure engineering-grade accuracy.
  • Geometric Limits: In Euclidean space, the central angle cannot exceed 360 degrees for a single circle analysis.
  • Measurement Error: Real-world applications must account for the thickness of the material, which might slightly alter the “effective” radius.

Frequently Asked Questions (FAQ)

Can a chord be longer than the circle’s diameter?

No. By definition, the longest chord in any circle is its diameter. If your inputs result in a chord longer than 2r, it is geometrically impossible.

How does the chord analysis calculator handle 180 degrees?

At exactly 180 degrees, the chord length is equal to the diameter (2r), and the sagitta is equal to the radius (r).

What is a sagitta?

The sagitta is the perpendicular distance from the center of the chord to the highest point of the arc. It is vital for calculating the “hump” of a curve.

Can I use this for non-circular ellipses?

This specific chord analysis calculator is designed for perfect circles. Elliptical chord analysis requires significantly different calculus.

Is the central angle required in radians?

While the internal formulas often use radians, this tool accepts degrees for user convenience and performs the conversion automatically.

Does the calculator provide the area of the whole circle?

The tool focuses on the segment area (the area between the chord and the arc), but the total circle area is always πr².

What is the relationship between chord length and arc length?

The arc length is always longer than the chord length, as the arc follows the curve while the chord is a straight line.

Is this calculator suitable for high-precision engineering?

Yes, the chord analysis calculator uses standard floating-point precision, suitable for architectural and mechanical engineering applications.


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