So I understand how to solve dimensional analysis problems in general. What I don't understand is how to incorporate square/cubic yards into the answer. Here's two examples that I can't find the right answer for:

1) LaShanda is buying carpet for a 15 feet x 12 feet room. How many square yards of carpet does she need to buy?

2) Ted is planning a cement patio that measures 12 feet x 18 feet. If he wants the cement slab to be 4 inches thick, how many cubic yards of cement must he order?

If anyone could break these down for me I'd really appreciate it.

Thank you.