Put two identical triangles together to form a parallelogram. The side lengths of the triangles are 7cm, 6cm and 3cm respectively. What is the longest perimeter of the assembled parallelogram in cmcm?
把两个完全一样的三角形拼成一个平行四边形，三角形的边长分别是7cm、6cm和3cm，拼成的平行四边形的周长最长是多少cmcm．
<gadget id="calculator">7 + 6</gadget>
<output>13</output>

<gadget id="calculator">13 * 2</gadget>
<output>26</output>

<result>26</result>