If you paint a pillar with a base diameter of 2 meters and a height of 45 decimeters, what is the painted area in square meters?
油漆一个底面直径为2米，高45分米的柱子，油漆面积是多少平方米．
<gadget id="calculator">45 / 10</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">3.14 * 2 * (9/2)</gadget>
<output>28.26</output>

<result>28.26</result>