In a right triangle, the ratio of the largest angle to the smallest angle is 5:1. What is the smallest angle of this triangle.
直角三角形中，最大角与最小角的比是5：1．这个三角形的最小角是多少度．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">90 * (1/5)</gadget>
<output>18</output>

<result>18</result>