The ratio of the apex angle to a base angle of an isosceles triangle is 3:1.
等腰三角形顶角与一个底角的度数比是3：1，它的顶角比一个底角大多少度．
<gadget id="calculator">3 + 1 + 1</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>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">180 * (1/5)</gadget>
<output>36</output>

<gadget id="calculator">108 - 36</gadget>
<output>72</output>

<result>72</result>