It is known that the degree ratio of the apex angle to a base angle of an isosceles triangle is 1:2, what is the base angle of the triangle
已知等腰三角形的顶角和一个底角的度数比是1：2，则三角形底角是多少
<gadget id="calculator">2 + 2 + 1</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>