The vertex angle of an isosceles triangle is 24°, what is the base angle?
等腰三角形中顶角是24°，底角是多少度．
<gadget id="calculator">180 - 24</gadget>
<output>156</output>

<gadget id="calculator">156 / 2</gadget>
<output>78</output>

<result>78</result>