Name: Surface Area of Hollow Cylinders
Uploaded: 2019-07-19
Duration: 6 min 11 s
Description: What do a tube and a drinking straw have in common? Both are cylindrical and have hollow ends. So, we call them hollow cylinders. Learn to find their surface...

Question

Find the lateral curved surface area of a cylindrical petrol storage tank that is

4.2 m

in diameter and

4.5 m

high. How much steel was actually used, if

\frac{1}{12}

of steel actually used was wasted in making the closed tank?

Accepted Answer

Given:

Diameter of the cylindrical tank ( $d$ ) $= 4.2 m$ .

$\Rightarrow$ Radius ( $r$ ) $= 2.1 m$ .

Height of cylindrical tank ( $h$ ) $= 4.5 m$ .

Now, lateral curved surface area of the tank $= 2 πrh$

LSA $= (2 \times \frac{22}{7} \times 2.1 \times 4.5) m^{2}$

$= (\frac{44}{7} \times 9.45) m^{2}$

$= 59.4 m^{2}$

Thus, the lateral curved surface area of the cylindrical petrol storage tank is $59.4 m^{2}$ .

Now, let us find the actual amount of steel used.

Total surface area $= [2 π r (r + h)]$

TSA $= 2 \times \frac{22}{7} \times 2.1 \times (2.1 + 4.5)$

$= \frac{44}{7} \times 2.1 \times 6.6$

$= 87.12 m^{2}$

Hence, the total surface area of the tank is $87.12 m^{2}$ .

It is also given that, $\frac{1}{12}$ of steel which was actually used was wasted in the making.

Let the amount of steel used $= a$ .

$\Rightarrow$ Amount of steel wasted $= \frac{a}{12}$

Now,

TSA $=$ Amount of steel used $-$ Amount of steel wasted

$87.12 = a - \frac{a}{12}$

$87.12 \times 12 = 11 a$

$1045.44 = 11 a$

$a = \frac{1045.44}{11}$

$a = 95.04$ .

Therefore, $95.04 m^{2}$ of steel was actually used in the making of the cylindrical petrol storage tank.

Find the lateral curved surface area of a cylindrical petrol storage tank that is $4.2 m$ in diameter and $4.5 m$ high. How much steel was actually used, if $\frac{1}{12}$ of steel actually used was wasted in making the closed tank?

Important Questions on Surface Area and Volume of a Right Circular Cylinder

Learn and Prepare for any exam you want !

Find the lateral curved surface area of a cylindrical petrol storage tank that is 4.2 m in diameter and 4.5 m high. How much steel was actually used, if 112 of steel actually used was wasted in making the closed tank?

Important Questions on Surface Area and Volume of a Right Circular Cylinder

Learn and Prepare for any exam you want !

Find the lateral curved surface area of a cylindrical petrol storage tank that is $4.2 m$ in diameter and $4.5 m$ high. How much steel was actually used, if $\frac{1}{12}$ of steel actually used was wasted in making the closed tank?