Question

Four cylindrical pillars of a building are to be painted. If the diameter of each pillar is 1.4m and it's height is 6m, find the cost of painting the curved surfaces of all the pillars at the rate of Rs 10 per.sq.m.​

Answer 1

Total cost of painting the curved surfaces of all the pillars is Rs 1056.

Explanation:

Given:

Diameter of Cylindrical pillar = 1.4 m

so radius will be equal to half of diameter.

radius r =
`(1.4)/(2) = 0.7\ m`

Height of cylinder = 6 m.

Number of cylindrical pillars =4

Cost of painting = Rs 10 per.sq.m.​

We need to find the cost of painting the curved surfaces of all the pillars

First we will find the curved surface area of cylindrical pillar.

Curved surface area of cylinder is given by 2 times π times radius times height.

framing equation form we get;

Curved surface area of cylinder =
`2\pi rh= 2\pi * 0.7* 6= 26.4\ m^2`

Now number of pillars in building = 4

Hence Total Curved surface area of cylindrical pillars will be equal to Curved surface area of 1 cylindrical pillar multiplied by number of pillars.

framing in equation form we get;

Total Curved surface area of cylindrical pillars =
`26.4*4 = 105.6 \ m^2`

Now given:

Cost of painting = Rs 10 per.sq.m.​

So Total cost of painting the curved surfaces of all the pillars is equal to Total Curved surface area of cylindrical pillars multiplied by Cost of painting.

Total cost of painting the curved surfaces of all the pillars =
`105.6*10 = Rs\ 1056`

Hence Total cost of painting the curved surfaces of all the pillars is Rs 1056.