A circular sector is a portion of a circle enclosed by two radii and an arc. It resembles a "pie slice" and is defined by its radius and the central angle it subtends.
Formula for Circular Sector Area
The formula to calculate the area of a circular sector is:
\[A = \frac{\theta}{360°} \pi r^2\]
Where:
\(A\) is the area of the circular sector
\(\theta\) (theta) is the central angle in degrees
\(\pi\) (pi) is approximately 3.14159
\(r\) is the radius of the circle
Calculation Steps
Identify the radius (r) of the circle.
Determine the central angle (θ) in degrees.
Divide the central angle by 360°.
Multiply the result by π (pi).
Multiply by the square of the radius.
The final result is the area of the circular sector in square units.
Example
Let's calculate the area of a circular sector with a radius of 5 units and a central angle of 60°:
Given:
Radius (r) = 5 units
Central Angle (θ) = 60°
Apply the formula: \(A = \frac{\theta}{360°} \pi r^2\)
Substitute the values: \(A = \frac{60°}{360°} \pi (5)^2\)
Calculate:
\(A = \frac{1}{6} \pi (25)\)
\(A = \frac{25\pi}{6}\)
\(A \approx 13.09\) square units (rounded to 2 decimal places)
Visual representation:
Therefore, the area of the circular sector is approximately 13.09 square units.
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