18.4.2 Line and Circle: Apart, Tangent, or Crossing
18.4 Point, Line, Circle — Who Touches Whom
Point 2 of 4
18.4.2 Line and Circle: Apart, Tangent, or Crossing
Core idea
Compare the distance d from the center to the line against r — d > r misses entirely, d = r just grazes at one point, d < r cuts through at two.
Module goal. Use one unifying key — comparing a distance against the radius — to judge how a point, a line, and two circles sit relative to one another.
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