Question

a cylindrical tower is 5m in diameter and 14m high. find the cost of whitewashing its curved surface at 10rupees/- per square metre​

Answer 1

Given :

a cylindrical tower is 5m in diameter and 14m high.

To find :

find the cost of whitewashing its curved surface at 10rupees/- per square metre

Solution :

⇛ r = 5/2 m

⇛ h = 14 m

curved surface area = 2πrh

⇛ 2 x 22/7 x 5/2 x 14

⇛ 2 x 22/7 x 5 x 7

⇛ 2 x 22 x 5 x 1

⇛ 44 x 5 x 1

⇛ 220 m²

now ,

cost of whitewashing

⇛ 220 x 10 rs

⇛ 2200 Rs

Answer 2

Given:

• Diameter= 5m
• Height= 14m

Need to Find:

• The cost of white washing

━━━━━━━━━━━━━━━━━━

The radius= Diameter÷ 2

==> Radius = 5÷2m

==> Radius = 2.5 m

━━━━━━━━━━━━━━━━━

We know,

Curved surface area:

= 2πrh

= 2× (22÷7)×2.5× 14 m²

=$\red{220m^2}$

━━━━━━━━━━━━━━━━━━

Cost of white washing:

=Curved surface area× Rate of white washing.

= 220× 10 Rupees

=$\red{2200Rupees}$