Equations of Circles

CHAPTER 17

17.1 Two Forms of Circle Equations

Form	Equation	Centre	Radius
Standard	$(x-h)^2 + (y-k)^2 = r^2$	$(h, k)$	$r$
General	$x^2 + y^2 + Dx + Ey + F = 0$	$(-\frac{D}{2}, -\frac{E}{2})$	$\sqrt{\frac{D^2}{4} + \frac{E^2}{4} - F}$

17.2 Tangent Properties

Tangent is perpendicular to radius

If distance from centre to line = radius → line is tangent

📘 MathsKiller Textbook Series | Chapter 17