The sides of an isosceles triangle are 3 cm and 7 cm respectively, what is its perimeter in cm?
等腰三角形的两边分别是3厘米和7厘米，它的周长是多少厘米．
<gadget id="calculator">7 + 7 + 3</gadget>
<output>17</output>

<result>17</result>