Uncle Zhang has a square vegetable field with a circumference of 48m. What is the area of this vegetable field?
张大爷有一块正方形的菜地，周长是48m，这块菜地的面积是多少㎡？
<gadget id="calculator">48 / 4</gadget>
<output>12</output>

<gadget id="calculator">12 * 12</gadget>
<output>144</output>

<result>144</result>