Question

a right circular cylinder is closed at both of ends.Find the cost of polishing its total surface at 25paise per square cm if the radius of the cylinder is 7cm and depth is 12cm

Answer 1

Answer:

Rs 209

Step-by-step explanation:

Hi,

Given radius of the cylinder = 7 cm

Given height of the cylinder = 12 cm

Total Surface Area of the cylinder =

    Curved Surface Area + lateral surface Area

Curved Surface Area is given by 2πrh

Lateral surface Area , since the cylinder is closed at both the ends, it would be equal to 2πr².

Hence Total Surface Area = 2πrh + 2πr²

= 2π*7*(7 + 12), Considering π = 22/7 we get

=836 cm².

Now, given that the cost of polishing is 25 paise per cm² i.e., Rs 1/4 /cm²

=> For polishing 836 cm², total cost would be Rs 836*1/4

= Rs 209

Hope, it helped !