72 students form a circle to play games on the playground. The distance between every two adjacent students is 2m. What is the circumference of this circle in m?
72个学生在操场上围成一个圆圈做游戏，每相邻两个同学之间都是2m，这个圆圈的周长是多少m．
<gadget id="calculator">2 * 72</gadget>
<output>144</output>

<result>144</result>