In an isosceles triangle, the ratio of the apex angle to the base angle is 1:2, what is the apex angle of this triangle?
一个等腰三角形，顶角与一个底角的比是1：2，这个三角形的顶角是多少度．
<gadget id="calculator">1 + 2 + 2</gadget>
<output>5</output>

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

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

<result>36</result>