The area of smaller segment of a circle cut off by chord of length 5cm...
Calculation of the area of the smaller segment of a circle
Given
- Length of chord = 5cm
- Angle subtended by the chord at the circumference = 30⁰
Conversion of degree to radian
As the formula for finding the area of a segment of a circle requires the angle to be in radians, we need to convert 30⁰ to radians.
1⁰ = π/180 radians
Therefore, 30⁰ = (30 x π)/180 radians = π/6 radians
Calculation of the area of the segment
The area of a segment of a circle can be calculated using the formula:
Area of segment = (θ/2) x r² - [(r x sinθ)/2]
Where:
- θ = Angle subtended by the chord at the center of the circle (in radians)
- r = Radius of the circle
In this case, we know that:
- θ = π/6 radians
- Length of chord = 5cm
To calculate the radius of the circle, we need to use the formula:
r = (c/2) x (1/sin(θ/2))
Where:
- c = Length of chord
- θ = Angle subtended by the chord at the center of the circle (in radians)
Substituting the given values, we get:
r = (5/2) x (1/sin(π/12))
Using a calculator, we get:
r ≈ 5.77cm
Now, substituting the values of θ and r in the formula for area of segment, we get:
Area of segment = ((π/6)/2) x (5.77)² - [(5.77 x sin(π/6))/2]
Using a calculator, we get:
Area of segment ≈ 1.55cm²
Conclusion
Therefore, the area of the smaller segment of the circle cut off by the chord of length 5cm subtending an angle 30⁰ at the circumference is approximately 1.55cm².