In a right triangle, the ratio of the degrees of the two acute angles is 5:4, what is the smaller angle?
一个直角三角形中，两个锐角的度数之比是5：4，则较小的一个角是多少゜
<gadget id="calculator">180 - 90</gadget>
<output>90</output>

<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">90 * (4/9)</gadget>
<output>40</output>

<result>40</result>