Geometria Circular — Calculadora Online Grátis
Circumference, area, diameter and arc length from radius or diameter
The Circle Calculator computes all circle measurements — area, circumference, diameter, and arc length for any central angle — from a single input of either the radius or diameter. It's useful for geometry students, machinists sizing circular parts, and anyone needing to calculate the properties of a circular region or path. Results update instantly as you change any input.
Frequently Asked Questions
Sobre Esta Calculadora
The circle is defined by a single measurement — its radius — from which all other properties follow. Area uses A = πr², circumference uses C = 2πr, and arc length for a central angle θ (in degrees) uses L = (θ/360)×2πr. These formulas appear throughout geometry, physics, and engineering.
The constant π ≈ 3.14159 is irrational — it cannot be expressed as a fraction — and is fundamental to all circle calculations. This calculator uses the full precision of π available in your browser's math library for accurate results.
Practical applications include calculating the area of circular gardens or pools, the circumference of wheels and gears, the arc length of curved roads and railways, and the cross-sectional area of pipes and cylinders. In physics, circular motion and wave propagation both depend heavily on these formulas.
Projete na medida a área ou raio usando PI.
Exemplo Resolvido
Circle properties from a radius of 7 cm
Entradas:
- Radius: 7 cm
- Central angle for arc: 120°
Passo a Passo:
- Diameter: d = 2r = 2 × 7 = 14 cm
- Circumference: C = 2πr = 2 × 3.14159 × 7 = 43.98 cm
- Area: A = πr² = 3.14159 × 49 = 153.94 cm²
- Arc length for 120°: L = (θ/360°) × C = (120/360) × 43.98 = 14.66 cm
- Sector area for 120°: A_sector = (θ/360°) × πr² = (120/360) × 153.94 = 51.31 cm²