A fence must be built to enclose a rectangular area of 20,000 square feet. Fencing material costs $4.00 per foot for the two sides facing north and south and $8.00 per foot for the other two sides. Find the cost of the least expensive fence. You must show your work.

Please note that you must answer all the questions with detailed work. You can make multiple posts for your original answers. Then reply to at least one post from your friend. All posts are due by Sunday 11:59 pm. If you only post the final answers or copy/paste answers from your friend's post or the internet without mentioning the source, you will receive a ZERO grade. Look at the Discussion Grading Rubrics to learn about how the Discussion posts are graded.