T. Sundara Row's Geometric exercises in paper folding (1905)
Sundara Rao, T. (Tandalam), b. 1853, Beman, Wooster Woodruff, 1850-1922, Smith, David Eugene, 1860-1944 · Chicago : Open Court · leaf 24
4 GEOMETRIC EXERCISES 8. A figure like this is called a rectangle. By superposition it is proved that (1) the four angles are right angles and all equal, (2) the four sides are not all equal. (3) but the two long sides are equal, and so also are the two short sides. 9. Now take a rectangular piece… … Fig. 5. falls upon one of the longer sides, DA' , as in Fig. 4. Then fold and remove the portion A' B'BA which overlaps. Unfolding the sheet, we find that ABCD is now square, i. e., its four angles are right angles, and all its sides are equal. 10. The crease which passes through a pair of the
Geometry · Paper work
Internet Archive · Wellesley College Library · Public domain (published before 1931). Free to use for anything.
![An illustration from Eyn schön nützlich Büchlin vnd Vnderweisung der Kunst des Messens mit dem Zirckel, Richtscheidt oder Linial : zu nutz allen Kunstliebhabern fürnemlich den Malern, Bildhawern, Goldschmiden, Seidenstikern, Steynmetzen, Scheinern auch allen Andern so sich der Kunst des Messens (Perspectiua zü latin gnant) zügebrauchen Lust haben : darin Man auch solche Kunst leichter dan ausz etzlichen hieuorgetruckten Büchern begreiffen vn lernen mag mit vil [i.e., 56] schönen darzü dienenden Figuren (1531)](https://img.insideoutlibrary.com/img/200/ia-eynschnntzlichbc00rodl-94-129.webp)
