An isosceles triangle, one of its top angles is 38 degrees, what is its one base angle in degrees.
一个等腰三角形，它的一个顶角是38度，它的一个底角是多少度．
<gadget id="calculator">180 - 38</gadget>
<output>142</output>

<gadget id="calculator">142 / 2</gadget>
<output>71</output>

<result>71</result>