Mathematical Methods · circle · manipulative

Circle equation — centre and radius

(x − h)² + (y − k)² = r² is the distance definition: every point on the circle is exactly r from the centre (h, k).

circle centre (h, k) radius r

Drag centre or radius handle · scroll zoom · drag pan · Shift+drag an axis to dilate

Parameters

0
0
1
Expanded form
show x² + y² + Dx + Ey + F = 0 alongside the centre–radius form

Working