The radius of the bottom of a cylindrical tea cylinder is 6cm, and the height is 7cm. What is its surface area?
一个圆柱形茶叶筒底面半径是6cm，高是7cm，它的表面积是多少．
<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">3.14 * 36 * 2</gadget>
<output>226.08</output>

<gadget id="calculator">3.14 * 6 * 2 * 7</gadget>
<output>263.76</output>

<gadget id="calculator">226.08 + 263.76</gadget>
<output>489.84</output>

<result>489.84</result>