Arectangular piece of land whose length is twice its width has a diagonal distance of 80 yards. how many yards, to the nearest tenth of a yard, does a person save by walking diagonally across the land instead of walking its length and its width?

Ibelieve appendix i maybe wrong

Ifound the exercise on the internet. attached is the list mentioned above.in order for a compound to be considered optically active it can't have any axis or plan of symmetry. the molecule  shouldn't also  be superimposable on its mirror image.with such considerations, the compounds that are optically active are: -third compound on the first image is optically active; -second and third compound from the second image are optically actives.