Cut out several pieces of rectangular paper with a length of 30 cm and a width of 12 cm from a piece of square paper, and there is nothing left. What is the minimum length of the side of this square paper?
在一张正方形纸上裁出长30厘米、宽12厘米的长方形纸片若干张，没有剩余，这张正方形纸的边长至少是多少厘米？
<gadget id="calculator">2 * 3 * 5 * 2</gadget>
<output>60</output>

<result>60</result>