Question

The slant height and base diameter of a conical tomb are 25m and 14m respectively. Find the cost of white washing it's curved surface at the rate of Rs 210 per 100m×100m

Answer 1

Given:-

Slant height= 25 m

Diameter= 14 m

White washing 100 m^2 =Rs.210

To find:-

Cost of white washing it's curved surface area

Solution:-

Diameter=14 m

$r = \frac{14}{2}$

$= 7 \: m$

Curved Surface Area= πrl

$= \frac{22}{7} \times 7 \times 25$

$= 550 \: {m}^{2}$

Cost of whitewashing 100 m^2 =Rs.210

$cost \: of \: 1 \: {m}^{2} \: area = \frac{1}{100} \times 210$

$= rs.2.1$

Cost of whitewashing 550 m^2= 550 × 2.1

=Rs.1155

________________________________

Therefore;

Cost of whitewashing the conical tomb= Rs.1155

Answer 2

ANSWER:-

Given:

The slant height and base diameter of a conical tomb are 25m and 14m respectively.

To find:

The cost of white washing its curved surface at the rate of Rs.210 per 100m× 100m.

Explanation:

We have,

• Slant height of conical tomb,l=25m
• Base-diameter of conical tomb,d= 14m
• Radius of conical tomb,r=14/2m
• Radius of conical tomb,r= 7m

We know that formula of the curved surface area of cone: πrl sq.unit

⇒ Curved surface area of conical tomb=( $\frac{22}{7}$× 7× 25)m²

⇒ Curved surface area of conical tomb=(22× 25)m²

⇒ Curved surface area of conical tomb= 550m².

Now,

Given,

⇒ Cost of whitewashing 100m² area = Rs.210

⇒ Cost of whitewashing 1m² area= $Rs.\frac{210}{100}$

⇒ Cost of whitewashing 1m² area= $Rs.\frac{21}{10}$

⇒ Cost of whitewashing 550m² area= $Rs.(\frac{21}{10} *550)$

⇒ Cost of whitewashing 550m² area= Rs.(21× 55)

∴ Cost of whitewashing 550m² area= Rs.1155.