Library/Geometry/Plane geometry/Area/Areas of curved figures

Areas of curved figures

Overview
Important

Curved figures include circles, ellipses, sectors, segments, and regions bounded by curves. Their areas are calculated using formulas derived from geometry, often involving extπ ext{π} and the properties of the figure (like radius or angle).

Important properties

  • The area of a circle is A=extπr2A = ext{π} r^2.

  • The area of a sector of a circle with central angle heta heta (in degrees) is A=θ360πr2A = \frac{\theta}{360} \pi r^2.

  • The area of a segment (a 'slice' cut off by a chord) can be found by subtracting the area of the triangle from the area of the sector.

  • Areas of more complex curved figures may require breaking them into simpler parts or using symmetry.