The bottom of a TV tower is a circle with a radius of 15 meters. In order to beautify the environment, Director Wang decided to plant a 5-meter-wide circular lawn around it. If a lawn costs 50 yuan per square meter, how much does it cost to grow a lawn?
某电视塔的底是半径为15米的圆形，王局长为了美化环境，决定在它的周围种5米宽的环形草坪．如果每平方米的草坪需要50元，那么要多少元才能种上草坪呢？
<gadget id="calculator">15 + 5</gadget>
<output>20</output>

<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">3.14 * 400</gadget>
<output>1_256</output>

<gadget id="calculator">15 ** 2</gadget>
<output>225</output>

<gadget id="calculator">3.14 * 225</gadget>
<output>706.5</output>

<gadget id="calculator">1_256 - 706.5</gadget>
<output>549.5</output>

<gadget id="calculator">50 * 549.5</gadget>
<output>27_475</output>

<result>27_475</result>