Question

FInd
1 - the lateral or curved surface area of a closed cylindrical petrol storage tank that is 4.2m in diameter and 4.5m high.
2 - Howe much steel was actually used , if 1/12 of the steel actually usernames was wasted in making the tank.

Answer 1

QUESTION:-

(i)Find the lateral or curved surface area of a closed cylindrical petrol storage tank that is 4.2m in diameter and 4.5m high.

(ii)How much steel was actually used , if 1/12 of the steel actually usernames was wasted in making the tank.

EXPLANATION:-

Lateral surface area of cylinder -:

$\longrightarrow \boxed{\bigstar\bf\;CSA=2\pi rh\bigstar}$

CSA=2×22/7×2.1×4.5      (Diametre=4.2 so radius=4.2/2 radius

CSA=2×22/7×9.45

CSA=59.4 m²

(ii)  in this case we will find the TSA :-

TSA of cylinder-:

$\longrightarrow \boxed{\bigstar\bf\;2\pi r(r+h)\bigstar}$

TSA=2×22/7×2.1(2.1+4.5)

TSA=2×22/7×2.1×6.6

TSA=27.72×22/7

TSA=87.12 m²

Now,

Let amount of steel=S

ATQ,

S-S/12=87.12

(11/12)S=87.12

S=95.04 m/s²

Hence , the area taken by steel = 54.45 m².

$\rule{150}{3}\bigstar\bigstar\bigstar\rule{150}{3}$

Answer 2

Given :-

• Diameter of Cylinder = 4.2m
• Height of Cylinder = 4.5 m

To Find :-

• C.S.A of Cylinder = ?
• Area taken to cover with steel except for the area taken by username on the surface of the Cylinder = ?

Solution :-

• To calculate the C.S.A and Area taken by steel at first we have to find C.S.A of Cylinder then calculate Area taken by steel on the surface of Cylinder. By applying formula you calculate it.

Formula Used :-

• C.S.A = 2 × π × r × h

• H = 4.5 m. R = D/2 => R = 4.2/2

⇢ C.S.A = 2 × 22/7 × 4.2/2 × 4.5

⇢ C.S.A = 22 × 4.2 × 4.5/7

⇢ C.S.A = 415.8/7

⇢ C.S.A = 59.4m²

• Now calculate area for steel here :-

⇢T.S.A of Cylinder = 2 × π × r (r + h)

⇢T.S.A = 2 × 22/7 × 4.2/2 × (4.2/2 + 4.5)

⇢T.S.A = 22 × 4.2 × 6.6/7

⇢T.S.A = 609.84/7

⇢T.S.A = 87.12m²

⇢ Area for steel = T.S.A of Cylinder + 1/12 of T.S.A used for username on the surface of Cylinder.

⇢ Area for steel = 87.12 + 1/12 × 87.12

⇢ Area for steel = 87.12 + 7.26

⇢ Area for steel = 94.38 m²

Hence, the csa of cylinder = 59.4 m².

Hence , the area taken by steel = 94.38 m².