14. A square-based pyramid has a base side length of $\sqrt{3}$ and all the edges of the lateral faces are $\sqrt{2}$. How many degrees does the angle between two edges not belonging to the same lateral face measure?
14. The answer is 120. The angle in question is the vertex angle of the isosceles triangle that has as its base the diagonal of the base and as its oblique sides two edges of the lateral faces. The base measures $\sqrt{6}$ and the ratio between the oblique side and half the base is $\frac{\sqrt{3}}{2}$ : this is the sine of half the angle in question. The measure of the angle is $120^{\circ}$.