Given two sheets of paper of the same size and form of When so folded take a fourth part off each. Part A in the figures. The question is now to cover quite exactly one of the remaining surfaces with the other, in cutting the latter in two perfectly equal parts. To resolve this question take the surface (parts A having been detached), with which it is intended to cover the other, In order to cover the other surface, Fig. 3, all that is now necessary is to lower the angles, viz.: angle A’, must be in front of angle A, angle B’ in front of angle B, and angle C’ in front of angle C. When the angles are lowered in this This experiment can be made either with one or the other sheet, in lowering or raising the angles. In the example shown here it is the fourth Figure which is destined to cover the other one. When the operation is terminated as indicated above, part M, of Fig. 4, will be at M’ of Fig. 3, and part O at O’ of the covert figure. |