The shape of a piece of glass is a triangle with a base of 12.5 decimeters and a height of 7.8 decimeters. The price of glass per square meter is 68 yuan. How much does it cost to buy this piece of glass?
一块玻璃的形状是一个三角形，它的底是12.5分米，高是7.8分米．每平方米玻璃的价钱是68元，买这块玻璃要用多少钱？
<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>