Pythagorean Theorem

Sum of four Squares

PDF) Lagrange's Four-Square Theorem

Euler's four-square identity

Solved In Number Theory, Lagrange's four-square theorem

What's so interesting about squared numbers? Lagrange's Four Square Theorem

PDF) Extended Lagrange's four-square theorem

Lagrange's 4 Square Theorem using Python

Waring's Problem & Lagrange's Four-Square Theorem

Chapter 3 Greek Number Theory The Role of Number Theory Polygonal, Prime and Perfect Numbers The Euclidean Algorithm Pell's Equation The Chord and Tangent. - ppt download

Why was this visual proof missed for 400 years? (Fermat's two square theorem)