免费圆计算器(进阶)
计算圆的面积、周长、直径，支持弧长和扇形面积。
deg
面积
78.5398
周长31.4159
直径10.0000
Arc Length7.8540
公式
## Circle Calculations ### Formulas - **Area** = pi × r² - **Circumference** = 2 × pi × r - **Sector Area** = pi × r² × (angle / 360) - **Arc Length** = 2 × pi × r × (angle / 360) A sector is a "pie slice" of the circle defined by a central angle.
计算示例
A circle with radius 5, find area and a 90-degree sector.
- 01Area = pi × 25 ≈ 78.5398
- 02Circumference = 2 × pi × 5 ≈ 31.4159
- 03Sector area = 78.5398 × 90/360 ≈ 19.6350
- 04Arc length = 31.4159 × 90/360 ≈ 7.8540
常见问题
What is a sector?
A sector is the region between two radii and an arc. Think of it as a "pie slice" of the circle.
How do I find the area if I know the diameter?
Divide the diameter by 2 to get the radius, then use A = pi × r². Alternatively, A = pi × d²/4.
What is the relationship between arc length and sector area?
Both are proportional to the central angle. Sector area = (1/2) × r × arc length.
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