64.

The above text has been translated into English, preserving the original text's line breaks and format.
2) As shown in Figure 1, in a $4 \times 4$ grid composed of small squares with a side length of 1, there are 25 grid points. Among the right-angled triangles with grid points as vertices, the number of right-angled triangles with the lengths of the two legs being 1 and 3 is $\qquad$ .