In an isosceles triangle, the ratio of the top angle to the bottom angle is 7:1, what is the top angle?
一个等腰三角形，顶角和底角的比为7：1，顶角是多少度．
<gadget id="calculator">7 + 1 + 1</gadget>
<output>9</output>

<gadget id="calculator">180 / 9</gadget>
<output>20</output>

<gadget id="calculator">20 * 7</gadget>
<output>140</output>

<result>140</result>