Question

Radius of cylinder is 14 dm and its height is 15 m. Find CSA and TSA

Answer 1

Given:

Radius of the cylinder = r = 14 dm

The height of the cylinder = h = 15 m

To be found:

The CSA - Curved Surface Area

And the TSA - Total Surface Area

So,

First, let's make the unit same -

14 dm = 1.4 m    [∵ 1 dm = 0.1 m or 10 dm = 1m]

Now,

The formula for finding,

CSA of cylinder = 2πrh unit sq.

And,

The formula for finding,

TSA of the cylinder = 2πrh + 2(πr²) unit sq.

Now,

Curved Surface Area of cylinder = 2πrh unit sq.

= $2 \times \frac{22}{7} \times 1.4 \times 15$

$= 2 \times 22 \times 3$

$\boxed{= 132\ m^{2}}$

And,

Total Surface Area of cylinder = 2πrh + 2(πr²) unit sq.

$= 123 + 2 (\frac{22}{7} \times (1.4)^{2})$  

[as we got 2πrh = 132]

$= 132 + 12.32$

$\boxed{=144.32 m^{2}}$

Hence,

Curved Surface Area of cylinder = 132 m sq.

And

Total Surface Area of cylinder = 144.32 m sq.

Answer 2

Given ,

Radius of cylinder (r) = 14 dm 1.4 m

Height of cylinder (h) = 15 m

As we know that , the curved surface area of cylinder is given by

$\boxed{ \tt{CSA = 2\pi rh}}$

Thus ,

$\tt \implies CSA = 2 \times \frac{22}{7} \times 1.4 \times 15$

$\tt \implies CSA = 44 \times 15 \times \frac{2}{10}$

$\tt \implies CSA = 44 \times 3$

$\tt \implies CSA = 132 \: \: {m}^{2}$

The CSA of cylinder is 132 m²

Now , the Total surface area of cylinder is given by

$\boxed {\tt{TSA = 2\pi rh + 2\pi {(r)}^{2} }}$

Thus ,

$\tt \implies TSA = 132 + 2 \times \frac{22}{7} \times {(1.4)}^{2}$

$\tt \implies TSA = 132 + \frac{44}{7} \times \frac{196}{100}$

$\tt \implies TSA = 132 + \frac{44 \times 28}{100}$

$\tt \implies TSA = 132 + 12.32$

$\tt \implies TSA = 144.32 \: \: {m}^{3}$

The TSA of cylinder is 144.32 m³