$(6$ points$).$ Suppose a management analyst wishes to predict demand for months for the next year.

Suppose average demand over the last $10$ years is as follows respective of month: January: $1200,$

February: $1500,$ March: $2000,$ April: $2100,$ May: $2000,$ June: $1900,$ July: $1900,$ August: $1800,$

September: $1500,$ October: $1200,$ and November: $800.$ Suppose that the average Seasonal Demand

over the last $10$ years is $1542$ and that the annual forecast for next year is $20000.$ Find December's

seasonal forecast for next year using the seasonal forecast method.