The base of a triangle is 20 cm, if it is reduced by a ratio of 4:5, what is the size of the reduced base in cm?
一个三角形的底为20厘米，按4：5的比缩小，缩小后的底为多少厘米．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">20 * (4/5)</gadget>
<output>16</output>

<result>16</result>