1. The problem says that the stone covers 29.26 square inches. So, the first thing you must do, is to convert 29.26 square inches (in²) to square feet (ft²):
1 in²=0.00694 ft², then:
29.26x0.00694= 0.20 ft²
2. The triangular area has the following surface:
A=bxh/2
A=(6 ft)(8 ft)/2
A=24.0 ft²
3. Finally, the number of stones (N) that cover the triangular area is:
N= 24.0 ft²/0.20 ft²
N=120 stones
Answer: Kiana should buy 120 stones to cover the triangular area in her backyard.
