Stage 18 · Circles

18.1.3 The Circle Is the Most Symmetric Shape of All

18.1 What Is a Circle — Definition and the Secret of Symmetry

Point 3 of 5

18.1.3 The Circle Is the Most Symmetric Shape of All

Core idea

Spin a circle any amount around its center and it lands on itself, fold it along any diameter and the halves match perfectly — it has both mirror symmetry and rotational symmetry.

Module goal. Start from the one core idea — every point the same distance from a fixed center — to understand the circle, then unearth its most powerful weapon, symmetry, laying the foundation for every theorem to come.
eastmath.com · 18.1 What Is a Circle — Definition and the Secret of Symmetry · 18.1.3 The Circle Is the Most Symmetric Shape of All