The ratio of the apex angle to the base angle of an isosceles triangle is 3:1, what is the apex angle in degrees?
等腰的三角形的顶角与底角的比是3：1，那么它的顶角是多少度．
<gadget id="calculator">1 + 1 + 3</gadget>
<output>5</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">180 * (3/5)</gadget>
<output>108</output>

<result>108</result>