A semicircular steel plate has a perimeter of 257 cm, what is the area of this steel plate in square centimeters?
一块半圆形的钢板，周长是257厘米，这块钢板的面积是多少平方厘米？
<gadget id="calculator">50 ** 2</gadget>
<output>2_500</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3.14 * 2_500 * (1/2)</gadget>
<output>3_925</output>

<result>3_925</result>