The perimeter of an isosceles triangle is 78 cm and the base is 28 cm long. What is the length of one of its sides in cm?
一个等腰三角形的周长是78厘米，底边长28厘米，它的一条腰长是多少厘米？
<gadget id="calculator">78 - 28</gadget>
<output>50</output>

<gadget id="calculator">50 / 2</gadget>
<output>25</output>

<result>25</result>