Answer :

Height (h) of cylindrical tank = 4.5 m

Radius (r) = () = 2.1 m

**(i)** Lateral or curved surface area of tank = 2πrh

= 2 × × 2.1 × 4.5

= (44 × 0.3 × 4.5) m^{2}

= 59.4 m^{2}

**Therefore, the CSA of the tank is 59.4 m ^{2}.**

**(ii)** Total surface area of tank = 2πr (r + h)

= 2 × × 2.1 × (2.1 + 4.5) m^{2}

= (44 × 0.3 × 6.6) m^{2}

= 87.12 m^{2}

Let x m^{2} steel sheet be actually used in making the tank

TSA = amount of steel - the amount of steel used

87.12 m

^{2}= x - x

x (1 - ) = 87.12 m^{2}

x = ( × 87.12) m^{2}

x = 95.04 m^{2}

**Therefore, 95.04 m ^{2} steel was used in making such a tank.**

Rate this question :

The lateral surfaRS Aggarwal & V Aggarwal - Mathematics

The diameter of aRS Aggarwal & V Aggarwal - Mathematics

The ratio betweenRS Aggarwal & V Aggarwal - Mathematics

The total surfaceRS Aggarwal & V Aggarwal - Mathematics

Which is false inRS Aggarwal & V Aggarwal - Mathematics

If the curved surRS Aggarwal & V Aggarwal - Mathematics

The curved surfacRS Aggarwal & V Aggarwal - Mathematics

A cylindrical rolNCERT Mathematics Exemplar