Make a parallelogram billboard with a base of 4.5m and a height of 2m. If 0.7kg of anti-rust paint is used per square meter, and both sides of the billboard need to be painted with anti-rust paint, how many kilograms of anti-rust paint is needed for this billboard?
做一个底是4.5m，高是2m的平行四边形广告牌．如果每平方米用防锈漆0.7kg，并且广告牌两面都需要漆防锈漆，这块广告牌需要用多少千克防锈漆？
<gadget id="calculator">4.5 * 2 * 0.7 * 2</gadget>
<output>12.6</output>

<result>12.6</result>