Answer:
It's not acceptable because the angle of the slope from the horizontal is to small (2°), probably the pipe won't be capable to drain
Step-by-step explanation:
If you know that the drain pipe runs a horizontal distance of 172 inches and drops 6 inches from the horizontal, you have that this both distances form a right triangle (90 ° with the horizontal)
Then you have to calculate the slope by The Pythagorean Theorem:
slope^2 = (side1) ^ 2 + (side2) ^ 2
where
side1 = 172 in
side2 = 6in
Put in what we know:
slope^2 = (side1)^2 + (side2)^2
slope^2 = (172)^2 + (6)^2
slope^2 = (172)^2 + (6)^2
slope^2 = 29620
slope = 
slope = 172,105
Which is almost the same measure the the horizontal side (172)
You can calculate the inclination angle, which is given by this equation:
sin (angle) = opposite side / hypotenuse (slope)
sin (angle) = 6 / 172,105
angle = arcsin (6 / 172,105) = inv sin (6 / 172,1051.9978798717 ° = 2 °
It is very small angle to drain