Circles and Semicircles (HSC SSCE Mathematics Advanced): Flashcards

Set of points equidistant from a fixed centre point

$x^2 + y^2 = r^2$

Pythagoras' theorem

$(pm r, 0)$

$(0, pm r)$

$y = sqrt{r^2 - x^2}$

$y = -sqrt{r^2 - x^2}$

$x = sqrt{r^2 - y^2}$

$x = -sqrt{r^2 - y^2}$

Half of a circle