There is a mirror with a length of 3 meters and a width of 1 meter. The price of the mirror is 15 yuan per square meter. How much does it cost to install this mirror?
有一面长3米，宽1米的镜子，镜子的价格是1平方米15元，安装这面镜子需要多少钱？
<gadget id="calculator">3 * 1 * 15</gadget>
<output>45</output>

<result>45</result>