The perimeter of an isosceles triangle is 58 centimeters, and the length of one of its sides is 19 centimeters, what is the length of its base in centimeters?
等腰三角形的周长是58厘米，它的一条腰的长度是19厘米，则它的底的长度是多少厘米．
<gadget id="calculator">19 * 2</gadget>
<output>38</output>

<gadget id="calculator">58 - 38</gadget>
<output>20</output>

<result>20</result>