Mom bought an isosceles triangle wind chime for Xiaohua, one of its base angles is 40°, what is its top angle?
妈妈给小华买了一个等腰三角形的风铃，它的一个底角是40°，它的顶角是多少度？
<gadget id="calculator">180 - 40 - 40</gadget>
<output>100</output>

<result>100</result>