Area of Circles and Sectors (HSC SSCE Mathematics Standard): Flashcards

$A = \pi r^2$

Distance from center to edge

Ring formed by two concentric circles

$A = \pi(R^2 - r^2)$

Slice bounded by two radii and an arc

$A = \frac{\theta}{360}\pi r^2$

Angle formed at the center of the circle

$A = \frac{1}{2}\pi r^2$

$A = \frac{1}{4}\pi r^2$

$R$ (capital)