The lengths of two adjacent sides of an isosceles triangle are 4cm and 8cm respectively, what is the perimeter of this triangle?
一个等腰三角形的相邻的两条边的长度分别是4cm和8cm，这个三角形的周长是多少．
<gadget id="calculator">4 + 4 + 4 + 4 + 4</gadget>
<output>20</output>

<result>20</result>