S2

Rotational Symmetry

旋转对称

Symmetry / 对称
Grades G4 - G7
👀

What It Looks Like

Recognition signals — when you see these, think of this structure:

  • 1Figures with multiple identical parts arranged in a circle
  • 2Questions about order of rotational symmetry
  • 3Patterns that repeat when turned
🎯

What It Really Tests

The core mathematical idea behind this structure:

A figure has rotational symmetry if it looks the same after being rotated by less than 360°.

如果图形旋转不到360°后看起来相同,则具有旋转对称性。

⚠️

Why Students Get Stuck

Common mistakes to watch out for:

  • Counting full 360° rotation as meaningful symmetry
  • Confusing order with angle of rotation
  • Missing that some figures have both reflection and rotation
💡

Your First Step

How to begin thinking about problems with this structure:

Find the smallest angle of rotation that brings the figure back to itself.

找到使图形回到自身的最小旋转角度。

Related Structures

These structures share similar patterns or thinking approaches: