A circular wooden cover is fitted to a cylinder mouth with a diameter of 5 decimeters. The diameter of the wooden cover is 1 decimeter larger than the diameter of the cylinder mouth. What is the area of the wooden cover in square decimeters?
给直径为5分米的缸口配上一个圆形的木盖，木盖的直径比缸口的直径大1分米，木盖的面积是多少平方分米．
<gadget id="calculator">5 + 1</gadget>
<output>6</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<result>28.26</result>