Question

What is the cross-sectional area of a cement pipe 2 in. thick with an inner diameter of 5 ft? Use pie 3.14.

Answer 1

Answer:

1.60 $ft^{2}$

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 = $\pi$$r^{2}$

So that,

for the inner part of the pipe,

r = $\frac{diameter}{2}$

 = $\frac{5}{2}$

 = 2.5 feet

Area of the inner part of the pipe = $\pi$$r^{2}$

                                 = 3.14 x $(2.5)^{2}$

                                 = 19.625

Are of the inner part of the pipe is 19.63 $ft^{2}$.

Total diameter of the pipe = 5 + 0.2

                                           = 5.2 feet

r = $\frac{5.2}{2}$

 = 2.6 feet

Area of the pipe = $\pi$$r^{2}$

                            = 3.14 x $(2.6)^{2}$

                            = 21.2264

Area of the pipe is 21.23 $ft^{2}$.

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 $ft^{2}$.