Xiaohong bought an isosceles triangle scarf, one of its top angles is 120°, what is its bottom angle?
小红买了一条等腰三角形的围巾，它的一个顶角是120°，它的底角是多少度？
<gadget id="calculator">180 - 120</gadget>
<output>60</output>

<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<result>30</result>