30.4 The Circle: Equation and Positional Relationships
Point 1 of 6
30.4.1 What Path Is a Circle?
Core idea
Pin one end of a string and swing the other end full around, and every point at the same distance r from the center traces a circle.
Module goal. Write the set of points equidistant from a fixed point as an equation, master the circle's two forms, and judge tangency and intersection with lines and other circles.
eastmath.com · 30.4 The Circle: Equation and Positional Relationships · 30.4.1 What Path Is a Circle?