A piece of triangular glass has a base of 12.5dm and a height of 7.8dm. The price per square meter is 68 yuan. How much does it cost to buy this piece of glass?
一块三角形玻璃，底是12.5dm，高是7.8dm，每平方米的价钱是68元，买这块玻璃要用多少元？
<gadget id="calculator">7.8 / 2 / 100</gadget>
<output>0.039</output>

<gadget id="calculator">12.5 * 0.039 * 68</gadget>
<output>33.15</output>

<result>33.15</result>