6. (3 points) Count the number of triangles in the figure: $\qquad$.

将上面的文本翻译成英文，请保留源文本的换行和格式，直接输出翻译结果。
6. (3 points) Count the number of triangles in the figure, which is 24.
【Analysis】Three points not on the same line can determine a triangle, according to this, the solution can be found.
【Solution】Solution: $(5+1+1+1+1)+(4+2+2+1)+3+2+1$
$$
\begin{array}{l}
=9+9+3+2+1 \\
=24 \text { (triangles) }
\end{array}
$$

Answer: There are 24 triangles in the figure.
Therefore, the answer is: 24.
【Comment】This problem mainly tests the understanding of triangles. Counting the number of triangles in the correct order is the key to solving this problem.