MathSimpler

Circles Basics

Learn circle fundamentals: definitions and properties, circumference, area, and sector concepts with calculations and real-world applications.

1. Basic Concepts & Properties
Radius, diameter, chord, tangent, symmetry
2. Circumference
Formulas C = 2πr = πd, examples, pitfalls
3. Area
Formula S = πr², scaling rules, applications
4. Sectors
Arc length and area in degrees/radians
🧮Circle Calculators
Interactive tools with calculation methods and related knowledge

Circle Area & Circumference

Compute area and circumference from radius or diameter.

  • Method: C = 2πr = πd; S = πr²
  • Related: radius–diameter relation (d = 2r), unit handling

Annulus (Ring) Area

Area between two concentric circles.

  • Method: S = π(R² − r²)
  • Related: difference of areas, scaling rules

Sector Arc & Area

Arc length and sector area in degrees or radians.

  • Method: L = rθ, S = ½r²θ (radians); use θ°/360° in degrees
  • Related: degree–radian conversion, central angle
🎯Practice: Circles Basics
Single-choice questions across properties, circumference, area, and sectors

Test conceptual understanding and calculations with instant feedback.