In an isosceles triangle, the apex angle is three times the base angle, what is the apex angle of this triangle?
一等腰三角形，它的顶角是一底角的3倍，这个三角形的顶角是多少度？
<gadget id="calculator">1 + 1 + 3</gadget>
<output>5</output>

<gadget id="calculator">180 / 5</gadget>
<output>36</output>

<gadget id="calculator">36 * 2</gadget>
<output>72</output>

<result>72</result>