Proof 2

Algebraic Proof

Version 1)

🍄 4 copies of a right angle triangle are arranged inside a square with an area of 2c (c squared), with 'c' on the outside edge

🌹 The triangles all have an area of ab/2

Version 2)

🍭 Similar to version 1, 4 copies of a right-angled arranged inside a square, but this time 'c' is on the inside.