The common properties in the two set-squares of a geometry box are that they have a ______ angle and they are of the shape of a _____.

In Fig. 9.10, if B is the image of the point A with respect to the line l and P is any point lying on l, then the lengths of line segments PA and PB are ______.

The number of lines of symmetry in Fig. 9.11 is _____.

The digits having only two lines of symmetry are ____ and _____.

The digit having only one line of symmetry is_____.