A piece of triangular glass has a base of 11.5 decimeters and a height of 8.4 decimeters. If the price of glass per square decimeter is 1.2 yuan, how much will it cost to buy this piece of glass?
一块三角形的玻璃，量得它的底是11.5分米，高是8.4分米．如果每平方分米玻璃的价钱是1.2元，买这块玻璃要用多少钱？
<gadget id="calculator">8.4 / 2</gadget>
<output>4.2</output>

<gadget id="calculator">11.5 * 4.2 * 1.2</gadget>
<output>57.96</output>

<result>57.96</result>