It is known that the ratio of the base angle to the apex angle of an isosceles triangle is 2:1, what is the apex angle in °?
已知一个等腰三角形的底角和顶角度数之比是2：1，顶角是多少°．
<gadget id="calculator">2 + 2 + 1</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>