The base angle of an isosceles triangle is 66°, what is the apex angle of this triangle?
一个等腰三角形的底角是66°，这个三角形的顶角是多少．
<gadget id="calculator">66 * 2</gadget>
<output>132</output>

<gadget id="calculator">180 - 132</gadget>
<output>48</output>

<result>48</result>