In an isosceles triangle, the measure of the apex angle is twice the measure of the base angle, what is the measure of the base angle?
一个等腰三角形中，顶角的度数是底角的2倍，它的底角是多少度．
<gadget id="calculator">1 + 1 + 2</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">180 * (1/4)</gadget>
<output>45</output>

<result>45</result>