The top angle of the red scarf is 150°, what is its bottom angle?
红领巾的顶角是150°，它的底角是多少度．
<gadget id="calculator">180 - 150</gadget>
<output>30</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<result>15</result>