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put this solution on YOUR website!Let's choose the working unit to be inches; therefore, height = 9 feet = 108 inches
Let x be the number of stairs. Each stair has a depth = 10 inches. We can therefore say that the horizontal length = 10*x
Slope = 3/4 = (y2-y1)/(x2-x1) = 108/10x.
If we solve for x: x=14.45
In order to see whether we need 14 or 15 stairs we need to try calculate the slope for both cases.
x = 14 implies slope=108/10*14=0.77
x = 15 implies slope=108/10*15=0.72
We know that the slope should not exceed 3/4=0.75 and therefore we choose x=15 no of steps.
Cristiana