There are 9 points that divide the circumference into nine equal parts. How many isosceles triangles are there with these points as vertices?
有9个点把圆周分成九等分，以这些点为顶点的等腰三角形有多少个．
<gadget id="calculator">4 * 9</gadget>
<output>36</output>

<result>36</result>