Learn how to use diagrams effectively and appropriately in mathematical reasoning. Discover the benefits and challenges of using diagrams to prove theorems and solve problems.

A rhombus has four congruent sides. A rectangle has four congruent angles. But a square has four congruent sides and four congruent angles. Using a Venn diagram, the relationship would look like this: ...

Venn had initially used diagrams developed by the Swiss mathematician Leonard Euler to show some relationships between sets, which he then developed into his famous Venn diagrams.