A billboard in the shape of a parallelogram has a base of 15 meters and a height of 9 meters. If you want to paint this billboard with paint. 0.6 kg of paint per square meter. At least how many kilograms of paint should be prepared?
一块平行四边形的广告牌，底是15米，高是9米．如果要用油漆漆这块广告牌．每平方米用油漆0.6千克．至少需要准备多少千克油漆？
<gadget id="calculator">15 * 9 * 0.6</gadget>
<output>81</output>

<result>81</result>