I’m assuming that you’re trying to read off the table at key “Area,” and place that value in the SmartDashboard under key “Area”. If that is what you’re trying to do, then use entry.getDouble (defaultValue) to convert from NetworkTableEntry to double. If that’s not what you’re trying to do, could you explain what you’re aiming for so that we could better help you?
putNumber(String key, double value) expects a String key (in your case, "Area") and a double value, but you are passing in table.getEntry("Area,"), which is of type NetworkTableEntry. Instead, you can do SmartDashboard.putNumber("Area", table.getEntry("Area,").getDouble(0.0)); to put in the entry’s double value rather than the entry itself. The 0.0 here is the default value, meaning that if it cannot find a value for the entry "Area,", it will return 0.0 instead.