There is an isosceles triangle, the ratio of its vertex angle to a base angle is 1:2, what is the vertex angle of this isosceles triangle in degrees?
有一个等腰三角形，它的顶角和一个底角度数的比是1：2，则这个等腰三角形顶角是多少°度．
<gadget id="calculator">2 / 1 / 2</gadget>
<output>1</output>

<gadget id="calculator">1 + 2 + 2</gadget>
<output>5</output>

<gadget id="calculator">2 / 1 / 2 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">180 * (1/5)</gadget>
<output>36</output>

<result>36</result>