The measure ratio of the apex angle to the base angle of an isosceles triangle is 1:2, what is the measure of the base angle?
一个等腰三角形的顶角与一个底角的度数比是1﹕2，它的一个底角的度数是多少．
<gadget id="calculator">1 + 2 + 2</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">180 * (2/5)</gadget>
<output>72</output>

<result>72</result>