Sector Area Calculator

Published on: February 23, 2025

Enter the radius and the central angle (in degrees) to compute the area of the sector.

Step-by-step method

  1. Identify what is given.
  2. Convert the angle from degrees to radians.
  3. Use the sector area formula.
  4. Substitute and calculate.

Formulas:

Formula: degrees to radians

θ(rad)=θ(°)×
π
180

Formula: sector area

A=½×r²×θ(rad)

Example 1: r = 4, θ = 60°

Step 1 - Identify what is given.

In this problem: The given values are r = 4 and θ = 60°.

r=4θ=60°

Step 2 - Convert the angle from degrees to radians.

In this problem: Convert degrees to radians using θ(rad) = θ(°) × π / 180.

θ(rad)=60×
π
180
=1.04719755

Step 3 - Use the sector area formula.

In this problem: Use the sector area formula A = ½ × r² × θ(rad).

A=½×r²×θ(rad)

Step 4 - Substitute and calculate.

In this problem: Substitute and calculate the area: A = 8.37758041.

A=½×4²×1.04719755=8.37758041

Final answer: A = 8.37758041

Example 2: r = 5.5, θ = 120°

Step 1 - Identify what is given.

In this problem: The given values are r = 5.5 and θ = 120°.

r=5.5θ=120°

Step 2 - Convert the angle from degrees to radians.

In this problem: Convert degrees to radians using θ(rad) = θ(°) × π / 180.

θ(rad)=120×
π
180
=2.0943951

Step 3 - Use the sector area formula.

In this problem: Use the sector area formula A = ½ × r² × θ(rad).

A=½×r²×θ(rad)

Step 4 - Substitute and calculate.

In this problem: Substitute and calculate the area: A = 31.67772592.

A=½×5.5²×2.0943951=31.67772592

Final answer: A = 31.67772592