A mountain road makes the horizontal
Answer:
1.60 
Step-by-step explanation:
Assuming that this is a cylindrical pipe, the area can be determined by applying the formula for calculating the area of a circle.
i.e Area = 

So that,
for the inner part of the pipe,
r = 
= 
= 2.5 feet
Area of the inner part of the pipe = 

= 3.14 x 
= 19.625
Are of the inner part of the pipe is 19.63
.
Total diameter of the pipe = 5 + 0.2
= 5.2 feet
r = 
= 2.6 feet
Area of the pipe = 

= 3.14 x 
= 21.2264
Area of the pipe is 21.23
.
Thus the cross sectional area = Area of the pipe - Area of the inner part of the pipe
= 21.2264 - 19.625
= 1.6014
The cross sectional area of the cement pipe is 1.60
.
We have to solve this equation:

Third degree polynomials like this one are not easily solved, but this one has a root at x = 0. The let us factorize this polynomial as x times a second degree polynomial:

Now we can find the roots of the quadratic polynomial as:
![\begin{gathered} x=\frac{-(-6)\pm\sqrt[]{(-6)^2-4\cdot1\cdot6}}{2\cdot1} \\ x=\frac{6\pm\sqrt[]{36-24}}{2} \\ x=\frac{6\pm\sqrt[]{12}}{2} \\ x=\frac{6\pm\sqrt[]{4\cdot3}}{2} \\ x=\frac{6\pm2\sqrt[]{3}}{2} \\ x=3\pm\sqrt[]{3} \\ x_1=3-\sqrt[]{3} \\ x_2=3+\sqrt[]{3} \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20x%3D%5Cfrac%7B-%28-6%29%5Cpm%5Csqrt%5B%5D%7B%28-6%29%5E2-4%5Ccdot1%5Ccdot6%7D%7D%7B2%5Ccdot1%7D%20%5C%5C%20x%3D%5Cfrac%7B6%5Cpm%5Csqrt%5B%5D%7B36-24%7D%7D%7B2%7D%20%5C%5C%20x%3D%5Cfrac%7B6%5Cpm%5Csqrt%5B%5D%7B12%7D%7D%7B2%7D%20%5C%5C%20x%3D%5Cfrac%7B6%5Cpm%5Csqrt%5B%5D%7B4%5Ccdot3%7D%7D%7B2%7D%20%5C%5C%20x%3D%5Cfrac%7B6%5Cpm2%5Csqrt%5B%5D%7B3%7D%7D%7B2%7D%20%5C%5C%20x%3D3%5Cpm%5Csqrt%5B%5D%7B3%7D%20%5C%5C%20x_1%3D3-%5Csqrt%5B%5D%7B3%7D%20%5C%5C%20x_2%3D3%2B%5Csqrt%5B%5D%7B3%7D%20%5Cend%7Bgathered%7D)
Then, the solutions to the equation are:
x = 0
x = 3 - √3
x = 3 + √3
Your answer is 8/5
If you plug it in, you get:
8/(2+3)
Add the 2 and 3 and you’ll get
8/5