The measure ratio of the apex angle to the base angle of an isosceles triangle is 5:2, what is the apex angle
一个等腰三角形顶角与底角的度数比5：2，则顶角是多少
<gadget id="calculator">5 + 2 + 2</gadget>
<output>9</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">180 * (5/9)</gadget>
<output>100</output>

<result>100</result>