10. A square is folded exactly in half and then in half again. Which of the following could not be the resulting shape?
10. D When a square is folded exactly in half, the shape obtained is a rectangle or a right-angled isosceles triangle. So to determine which c the given shapes can be obtained from a second fold we need to test which shapes form a rectangle or a right-angled isosceles triangle when joined with the image formed when the shape is reflected about an edge. Of the options given, only D does not do this. Of the others, shape $\mathrm{A}$ is formed by using fold line 1 first, followed by fold line 3 . For shape B the fold lines are 3 followed by 4 . For shapes $\mathrm{C}$ and $\mathrm{E}$, which are similar, the fold lines are 2 followed by 5 .