Given that the side length of square ABCD is 7 cm, and E, F, G, H are the midpoints of the sides of square ABCD, find the area of square EFGH.
已知正方形ABCD的边长是7厘米，E、F、G、H分别为正方形ABCD各边的中点，求正方形EFGH的面积．
<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">7 * (7/2)</gadget>
<output>49/2 = around 24.5</output>

<result>49/2 = around 24.5</result>