The ratio of the three interior angles of a triangle is 3:6:9, what is the largest angle of this triangle?
一个三角形三个内角的比是3：6：9，这个三角形最大的角是多少度．
<gadget id="calculator">3 + 6 + 9</gadget>
<output>18</output>

<gadget id="calculator">9 / 18</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">180 * (1/2)</gadget>
<output>90</output>

<result>90</result>