What is the perimeter of an isosceles triangle with a side length of 8 cm and a side length of 3.5 cm?
一个等腰三角形，一条边长是8厘米，领一条边长是3.5厘米，它的周长是多少．
<gadget id="calculator">8 + 8 + 3.5</gadget>
<output>19.5</output>

<result>19.5</result>