The apex angle of an isosceles triangle is 30 degrees, and the measure of the apex angle is equal to the measure of the base angle.
一个等腰三角形的顶角是30度，顶角的度数是底角度数的多少．
<gadget id="calculator">180 - 30</gadget>
<output>150</output>

<gadget id="calculator">150 / 2</gadget>
<output>75</output>

<gadget id="calculator">30 / 75</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>