Question

The diameter of a well is 3 m and the depth is 14 m. Find the cost of plastering the well if
the plastering cost is ? 8 per sq.m.​

Answer 1

Answer:

the diameter of the well = 3 m

and radius (r) = 3/2

height of well = 14 m

curved surface area of the well = 2πrh

= 2×22/7×3/2×14

= 132m^

so,the cost of plastering the well if the plastering cost is 8 per sq.m. = 8×132

= 1,056

Answer 2

Given -

• Diameter of well = 3m

• Depth of well = 14m

To find -

• Cost of plastering the well.

Formula used -

• Curved surface area of Cylinder = 2πrh

Solution -

In the question, we are provided with the diameter and the depth of a well, and we need to find the cost of plastering the well. So, for that, first we will convert the given diameter into radius, by dividing it by 2, as radius is half of diameter. Then we will use the formula of curved surface area of cylinder, after that we will multiply the obtained curved surface area with ₹8, that will give us the cost of plastering. Let's do it!

According to question -

Depth = Height of well = 14 m

Diameter = 3 m

So -

First we will convert the given diameter into radius.

Radius = $\sf\dfrac{3}{2}$ m

Radius = 1.5 m

Now -

We will apply the formula of. curved surface area of cylinder, for that we should have radius, height. Let's do it!

$\sf \longrightarrow \: csa \: = 2\pi \: r \: h \\ \\ \\ \sf \longrightarrow \: csa \: = 2 \: \times \dfrac{22}{7} \: \times 1.5 \: m \: \times 14 \: m \\ \\ \\ \sf \longrightarrow \: csa \: = 2 \: \times 22 \: \times \: 1.5 \: m \: \times \: 2 \: m \\ \\ \\ \sf \longrightarrow \: csa \: = 132 \: {m}^{2}$

At the end -

We will find the cost of plastering the well, by multiplying 132 with 8, that will give us cost.

$\sf \longrightarrow \: cost \: = 132 \: \times \: rs.8 \\ \\ \\ \sf \longrightarrow \: cost \: = rs. 1056$

$\therefore$ The curved surface area of well is 132m² and cost of plastering is ₹1056.

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