The formula for the area of a triangle is 1/2bh where b is the base and h is the height. So, you would do 1/2(22)(10). 1/2 times 22, or 22 divided by two, is 11. 11 times 10 is 110. This means that the area of the triangular area is 110 square feet. If each bag of mulch covers 8 square feet, divide 110 by 8 leaving you with 13 3/4 or 13.75. You typically can't buy a third of a bag of mulch, so you will need 14.
