There is an equilateral triangle flower bed in the school garden, each side of the flower bed is 7 meters long, what is the perimeter of the flower bed in meters?
学校花园里有一个等边三角形的花坛，花坛每边长7米，这个花坛的周长多少米？
<gadget id="calculator">3 * 7</gadget>
<output>21</output>

<result>21</result>