There is a triangular street billboard with a base length of 2.5 meters and a height of 4 meters. If this billboard is to be decorated with oil, 0.8 kilograms of paint is needed per square meter. How many kilograms of paint are needed in total?
有一块底边长为2.5米，高为4米的三角形状的街头广告牌，如果要油饰这块广告牌，每平方米需要用油漆0.8千克，共需要多少千克油漆？
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">2.5 * 2 * 0.8</gadget>
<output>4</output>

<result>4</result>