# Sector Area Calculator

> Calculate the area, arc length, and perimeter of a circular sector from its radius and central angle

**Category:** Math
**Keywords:** sector, circle, area, arc, geometry, radians, degrees, perimeter, chord, central angle, pizza slice
**URL:** https://complete.tools/sector-area-calculator

## How it calculates

The calculations for the area, arc length, and perimeter of a circular sector can be performed using the following formulas: 

1. Area (A) = (θ ÷ 360) × π × r², where θ is the central angle in degrees and r is the radius. 
2. Arc Length (L) = (θ ÷ 360) × 2 × π × r. 
3. Perimeter (P) = L + 2r. 

In these formulas, π (pi) is approximately 3.14159. The area formula calculates the proportion of the circle's total area based on the central angle. The arc length formula computes the length of the curved edge, while the perimeter formula sums the arc length with the lengths of the two radii, providing the total distance around the sector. Each variable is essential for determining the respective properties of the sector.

## Who should use this

Architects designing circular structures may need to calculate segment areas for material estimates. Physicists might use the tool when analyzing circular motion and related phenomena. Surveyors could apply it for land division that involves circular plots. Additionally, graphic designers may find it useful for creating circular diagrams or infographics that require precise sector dimensions.

## Worked examples

Example 1: Calculate the area, arc length, and perimeter of a sector with a radius of 5 cm and a central angle of 60 degrees. 

Area: A = (60 ÷ 360) × π × (5)² = (1/6) × π × 25 ≈ 13.09 cm². 
Arc Length: L = (60 ÷ 360) × 2 × π × 5 = (1/6) × 10π ≈ 5.24 cm. 
Perimeter: P = 5.24 + 2 × 5 = 5.24 + 10 = 15.24 cm. 

Example 2: Consider a sector with a radius of 10 m and a central angle of 90 degrees. 

Area: A = (90 ÷ 360) × π × (10)² = (1/4) × π × 100 = 25π ≈ 78.54 m². 
Arc Length: L = (90 ÷ 360) × 2 × π × 10 = (1/4) × 20π = 5π ≈ 15.71 m. 
Perimeter: P = 15.71 + 2 × 10 = 15.71 + 20 = 35.71 m.

## Limitations

The tool operates under certain assumptions that may limit its accuracy. First, it assumes the central angle is provided in degrees; using radians could yield incorrect results without conversion. Second, the tool does not account for significant figures in the radius or angle, which may affect precision. Third, calculations are based on an ideal circular shape; real-world applications involving physical materials may introduce factors such as material thickness or curvature that are not considered here. Lastly, very small angles may lead to negligible arc lengths and areas, resulting in less meaningful outputs.

## FAQs

**Q:** How does the central angle affect the area of a sector?


**A:** The central angle directly influences the area, as a larger angle results in a proportionally larger area, calculated as a fraction of the full circle.


**Q:** Can the tool handle angles greater than 360 degrees?


**A:** While the tool can compute with any angle, angles greater than 360 degrees will simply represent multiple full circles, which may not have practical geometric significance for a single sector.


**Q:** What is the significance of using radians instead of degrees?


**A:** Using radians is important in certain mathematical contexts, as many formulas in calculus and physics use radians for angular measurements, affecting calculations involving circular motion.


**Q:** How can errors in input values affect the results?


**A:** Errors in the radius or angle inputs will lead to proportional errors in calculated area, arc length, and perimeter, highlighting the importance of accurate measurements.

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