Dad bought Xiaoqing an isosceles triangle kite. One of its base angles is 75°, what is its top angle in degrees?
爸爸给小晴买了一个等腰三角形风筝．它的一个底角是75°，它的顶角是多少度．
<gadget id="calculator">75 * 2</gadget>
<output>150</output>

<gadget id="calculator">180 - 150</gadget>
<output>30</output>

<result>30</result>