you find the volume of the flower bed (4 times 25 time 6) this is 600. but you then realize that you need to convert the 6 inches into ft. so you do 25 times 4 /2 which is 50. 50/9 is rounded up to 6. Just notes: Although, when you do this, your units are in ft squared. you need to get them into yards. there are 3 feet in one yard. So, divide 600 by 9. (you need to multiply 3 times 3 to cancel out the ft squared). your answer is a