In an isosceles triangle, the ratio of the degrees of the top angle to the bottom angle is 1:2, what is the top angle?
在等腰三角形中，顶角和底角的度数之比是1：2，则顶角是多少．
<gadget id="calculator">2 / 1 / 2</gadget>
<output>1</output>

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

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

<result>36</result>