We are asked to find the area of the minor segment of a circle. The central angle of the segment is $60^{\circ}$ and the radius of the circle is 22 cm.

GeometryArea CalculationCircleSectorTriangleSegmentTrigonometry
2025/4/26

1. Problem Description

We are asked to find the area of the minor segment of a circle. The central angle of the segment is 6060^{\circ} and the radius of the circle is 22 cm.

2. Solution Steps

The area of the minor segment is the area of the sector minus the area of the triangle formed by the two radii and the chord.
First, let's find the area of the sector. The area of a sector with central angle θ\theta (in degrees) and radius rr is given by:
Areasector=θ360πr2Area_{sector} = \frac{\theta}{360^{\circ}} \pi r^2
In this case, θ=60\theta = 60^{\circ} and r=22r = 22 cm.
Areasector=60360π(22)2=16π(484)=484π6=242π3Area_{sector} = \frac{60^{\circ}}{360^{\circ}} \pi (22)^2 = \frac{1}{6} \pi (484) = \frac{484\pi}{6} = \frac{242\pi}{3} cm2^2.
Next, let's find the area of the triangle. Since the central angle is 6060^{\circ} and the two sides are equal to the radius (22 cm), this is an isosceles triangle. Since the angles opposite to equal sides of an isosceles triangle are equal, the other two angles are equal to 180602=1202=60\frac{180^{\circ}-60^{\circ}}{2} = \frac{120^{\circ}}{2} = 60^{\circ}. Thus, this triangle is an equilateral triangle with side length 22 cm.
The area of an equilateral triangle with side length ss is given by:
Areatriangle=34s2Area_{triangle} = \frac{\sqrt{3}}{4} s^2
In this case, s=22s = 22 cm.
Areatriangle=34(22)2=34(484)=1213Area_{triangle} = \frac{\sqrt{3}}{4} (22)^2 = \frac{\sqrt{3}}{4} (484) = 121\sqrt{3} cm2^2.
Now, we can find the area of the minor segment by subtracting the area of the triangle from the area of the sector:
Areasegment=AreasectorAreatriangle=242π31213Area_{segment} = Area_{sector} - Area_{triangle} = \frac{242\pi}{3} - 121\sqrt{3} cm2^2.
Using π3.14159\pi \approx 3.14159 and 31.73205\sqrt{3} \approx 1.73205,
Areasegment242×3.141593121×1.73205760.264783209.57805253.42159209.5780543.84354Area_{segment} \approx \frac{242 \times 3.14159}{3} - 121 \times 1.73205 \approx \frac{760.26478}{3} - 209.57805 \approx 253.42159 - 209.57805 \approx 43.84354 cm2^2.
Areasegment=242π31213=121(2π33)Area_{segment} = \frac{242\pi}{3} - 121\sqrt{3} = 121(\frac{2\pi}{3} - \sqrt{3})
The approximate value is 121(2×3.1415931.73205)121(2.094391.73205)121(0.36234)43.84314121(\frac{2 \times 3.14159}{3} - 1.73205) \approx 121(2.09439 - 1.73205) \approx 121(0.36234) \approx 43.84314 cm2^2.

3. Final Answer

242π31213 \frac{242\pi}{3} - 121\sqrt{3} cm2^2 which is approximately 43.84 cm2^2.

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