Plane Figure with Bilateral Symmetry about Two Lines has 4 Congruent Parts

Theorem

Let $F$ be a plane figure.

Let $F$ have two different axes of bilateral symmetry.

Then those two axes divide $F$ into $4$ congruent parts.

Proof

This theorem requires a proof. In particular: More background needed on the geometry of symmetry. You can help $\mathsf{Pr} \infty \mathsf{fWiki}$ by crafting such a proof. To discuss this page in more detail, feel free to use the talk page. When this work has been completed, you may remove this instance of {{ProofWanted}} from the code. If you would welcome a second opinion as to whether your work is correct, add a call to {{Proofread}} the page.

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $4$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $4$