【超基础】计算矩形面积的输出问题？

/**
   A program that computes the area of a rectangle
   and prints it out.
   All variables should be of type double.
*/
public class RectArea
{
   public static void main (String[] args)
   {
      double width = 4.25;
      double height = 3.40;

      // Compute the area of the rectangle and print it out

      // Your work here
      System.out.printIn (4.25 * 3.40);

   }
}

错误提示：

Error:

/tmp/codecheck.ZARFRR8tpj/RectArea.java:16: error: cannot find symbol
      System.out.printIn (4.25 * 3.40);
                ^
  symbol:   method printIn(double)
  location: variable out of type PrintStream
1 error

疑问：是我的输出没有转换为double类型吗？

刚接触java，求教各位大大！

System.out.println

ln是 line 的缩写
In 是什么？