A piece of square cloth can be made into a small square handkerchief with a side length of 18cm, or a handkerchief with a side length of 30cm, and there is nothing left over. What is the minimum length of the sides of this square piece of cloth?
一块正方形布料，既可以做成边长是18cm的小正方形手帕，又可以做成边长是30cm的手帕，都没有剩余．这块正方形布料的边长至少是多少厘米．
<gadget id="calculator">2 * 3 * 3 * 5</gadget>
<output>90</output>

<result>90</result>