Question

11.Determine the metal required to make a 21 m long pipe if its inner and outer diameter are 12 m and 10 m respectively.

Answer 1

R = outer radius=6m
r = inner radius=5m
metal required = pi*(R^2 - r^2)*h, h=21=
3.14*(36-25)*21=725.34 cubic meter...

Answer 2

Answer:

726 cubic m

Step-by-step explanation:

Given : Height of pipe = 21 m

            Inner diameter = 12 m

            Outer Diameter = 10 m

To Find : Determine the metal required to make a 21 m long pipe

Solution:

Material required for pipe = Outer volume - Inner Volume

Pipe is in the Shape of Cylinder

Volume of Cylinder = $\pi r^2h$

Outer diameter = 12 m

Outer radius (R)= $\frac{12}{2}=6 m$

Outer Volume= $\frac{22}{7} \times 6^2 \times 21$

                      = $2376 m^3$

Inner Diameter = 10 m

Inner Radius r = $\frac{10}{2}=5 m$

Inner Volume = $\frac{22}{7} \times 5^2 \times 21$

                      = $1650m^3$

So, Material required for pipe = Outer volume - Inner Volume

Material required for pipe = 2376-1650

                                            = 726 cubic m

Hence  the metal required to make a 21 m long pipe is 726 cubic m