Question

Find (1) the lateral or curved surface area of a closed cylindrical petrol storage tank that is 4.2 m in diameter and 4.5 m high. (ii) how much steel was actually used, if 1by12of the steel actually used was wasted in making the tank.​

Answer 1

HEY MATE HERE IS YOUR EXPLAINATION AND ANSWER

Answer

• Answer(i)Diameter of a cylindrical(closed) petrol tank=4.2 m

=Radius=

=2

=4.2

4.2

4.2 =2.1 m

=Height=4.5 m

=Curved Surface area=2πrh=2×

=7

=22

22

= ×2.1×4.5=59.4sq.m

• ×2.1×4.5=59.4sq.m(ii)Total surface area=2πr(r+h)=2×

=7

=22

22

= ×2.1×(2.1+4.5)=2×

=7

=22

22

= ×2.1×6.6=87.12 sq.m

• ×2.1×6.6=87.12 sq.mLet the amount of steel used in making the tank=x

• ×2.1×6.6=87.12 sq.mLet the amount of steel used in making the tank=xSteel wasted=

=12

=x

x

x

• x Given:Amount of steel required−Amount of steel wasted=T.S.A of the tank.

=⇒x−

=12

=x

x

x =87.12

x =87.12⇒

=12

=12x−x

12x−x

= =87.12

=87.12⇒

=12

=11x

11x

= =87.12

=⇒x=

=11

=12

12

= ×87.12=95.04sq.m

=∴95.04sq.m steel was used in actual while making such a tank.

hopefully it will help u ☺️✌️