The apex angle of an isosceles triangle is 40°, and the measure of the apex angle is ((())/(())) of the base angle.
一个等腰三角形的顶角是40°，顶角的度数是底角度数的((())/(()))．
<gadget id="calculator">180 - 40</gadget>
<output>140</output>

<gadget id="calculator">140 / 2</gadget>
<output>70</output>

<gadget id="calculator">40 / 70</gadget>
<output>4/7 = around 0.571429</output>

<result>4/7 = around 0.571429</result>