The first example: the side length of a square is 1 cm, so the diagonal length is 2 cm.

The second example: the area of a square is 2 square centimeters, so the side length of a square is 2 centimeters.

When you say double root number 3, it's actually not double root number 3, but double root number 3. It looks a bit like twice the root number 3, but it is a little small, in the upper left corner of the root number. As shown in the picture, it is written like this. The picture is being uploaded, please wait a moment.