In an isosceles triangle, one base angle is 60° greater than the apex angle, what is the apex angle?
一个等腰三角形，一个底角比顶角大60°，它的顶角是多少度．
<gadget id="calculator">60 * 2</gadget>
<output>120</output>

<gadget id="calculator">180 - 120</gadget>
<output>60</output>

<gadget id="calculator">60 / 3</gadget>
<output>20</output>

<result>20</result>