A triangular billboard has a base of 5.2 meters and a height of 4 meters. If 0.78 kilograms of paint is used per square meter and both sides are painted, how many kilograms of paint is needed to paint this billboard?
一个三角形的广告牌，底是5.2米，高是4米，如果每平方米用油漆0.78千克，两面都要刷，刷这个广告牌需要多少千克油漆？
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">5.2 * 2 * 2 * 0.78</gadget>
<output>16.224</output>

<result>16.224</result>