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About Arc Length

The distance along a portion of the circumference of any circle or curve is best characterised as arc length (arc). The arc length is any distance along the curved line that makes up the arc. Arc refers to a portion of a curve or the circumference of a circle. Their shapes all have a curvature to them. An arc's length is greater than any straight line distance between its ends (a chord).

What is Arc Length?

The interspace between two locations along a portion of a curve is defined as the arc length. Any section of a circle's circumference is considered an arc. An arc's subtended angle at any location is the angle generated by the two line segments connecting that point to the arc's endpoints. OP, for example, is the arc of the circle with centre Q in the diagram below. L denotes the arc length of this arc OP.

Arc Length Formula

Different formulas can be used to compute the length of an arc based on the unit of the arc's central angle. The centre angle can be measured in degrees or radians, and the arc length of a circle is calculated appropriately. The arc length formula for a circle is times the radius of a circle.

The arc length formula in radians can be expressed as 

arc length = θ × r, when θ is in radians. 

Arc Length (L) = θ × (π/180) × r, where θ is in degree, where,

L = Length of an Arc

θ = Central angle of Arc

r = Radius of the circle

Arc Length Formula in Radians

Different formulas can be used to compute the arc length of a circle based on the unit of the arc's centre angle. The arc length formula in radians is as follows:

Arc Length = θ × r

where,

L = Arc Length

θ = Centre angle of the arc in radians

r = Radius of the circle

To get all the Maths formulas, check out the main page. 

Importance of Arc Length Formula

The arc length formula is important in geometry, trigonometry, engineering, and construction. It is used to measure curved surfaces and circular paths accurately. Students also use this formula in school mathematics and competitive examinations.

Arc length calculations are commonly applied in:

  • Circular tracks and wheels
  • Engineering designs
  • Architecture and construction
  • Geometry and mensuration problems

Example

Suppose a circle has a radius of 7 cm and a central angle of 90∘90^\circ90.

Using the formula:

L=90360×2π×7L=\frac{90}{360}\times2\pi\times7

L=90/360×2π×7 L=14×14πL=\frac{1}{4}\times14\pi=3.5π cm

So, the arc length is 3.5π3.5\pi3.5π cm.

Conclusion

The Arc Length Formula is a useful mathematical formula for finding the length of a curved section of a circle. Understanding this formula helps students solve geometry problems accurately and apply circle concepts in practical situations. Regular practice improves calculation speed and strengthens geometry fundamentals.

 

FAQs for Arc Length Formula

The arc length formula calculates the distance along a curve or circular segment. For a circle, it is given by:
L=rθ
where L is the arc length, r is the radius, and θ is the central angle in radians. This formula is essential in geometry, physics, and engineering applications.

If the central angle θ\thetaθ is in degrees, use the formula:
L=πrθ/180. This conversion helps in practical problems where angles are given in degrees instead of radians.

The arc length formula is widely used in architecture, road construction, satellite dish designs, and physics to measure curved distances, design circular structures, and calculate trajectories.

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