Answer: 108.75 inches or 9.0625 ft
This is equivalent to 9 ft + 0.75 of an inch, or 9 ft + 3/4 of an inch
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Work Shown:
7 & 1/4 = 7.25
Each riser is 7.25 inches tall
15 of them gives a total height of 15*7.25 = 108.75 inches
Divide that by 12 to convert to feet
108.75/12 = 9.0625 feet
9.0625 ft = 9 ft + 0.0625 ft
9.0625 ft = 9 ft + (0.0625 ft)*(12 inches/1 ft)
9.0625 ft = 9 ft + 0.75 inches
9.0625 ft = 9 ft + 3/4 of an inch