The History of Mathematical Proof in Ancient Traditions

Contextualizing Playfair and Colebrooke 253

Figure 5.6 Th e square ( a + b ) 2.

8 × 8

Figure 5.7 Th e area ( a + b )^2 minus the squares a 2 and b 2 equals twice the product ab.

3

5

5 × 3

3 × 5

In other words, from Figure 5.6, delete the sum of the squares: which is
3 × 3 and 5 × 5.