A piece of trapezoidal glass has an upper base of 0.6 meters, a lower base of 1.5 meters, and a height of 0.8 meters. If the unit price of glass per square meter is 20 yuan, how much does it cost to buy this piece of glass?
一块梯形玻璃，上底是0.6米，下底是1.5米，高0.8米，如果每平方米玻璃的单价是20元，买这块玻璃需要多少元钱？
<gadget id="calculator">0.6 + 1.5</gadget>
<output>2.1</output>

<gadget id="calculator">0.8 / 2</gadget>
<output>0.4</output>

<gadget id="calculator">2.1 * 0.4 * 20</gadget>
<output>16.8</output>

<result>16.8</result>