Question

Asif is building a bird house .The roof of the bird house is in the form of right circular cone whose radius is 21cm and slant height is 47cm. He plans to paint the roof red but he needs to know the surface area to buy right amount of paint . What is the surface area of the roof?

5808 sqcm

 3102 sqcm

8058 sqcm

3120 sqcm


tell me the answer please
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Answer 1

Answer:

3102 sq.cm

Step-by-step explanation:

Radius of the roof= 21 cm

Slant height of the roof=47 cm

The roof is cone shaped.To colour the roof,only lateral surface area is needed.

So,Lateral surface area of the roof of the bird house= πrl (where r=radius,l=slant height)

= (22÷7×21×47) sq.cm

= (22×47×3) sq.cm

= 3102 sq.cm

Here is your answer.I have provided a diagram for you to understand quickly

Answer 2

Answer:

3102 $cm^{2}$

Step-by-step explanation:

Radius of cone = 21cm

Slant height ($l$) = 47cm

Surface area of roof = CSA of Cone

$= \pi rl\\= (\frac{22}{7} ) (21) (47)\\= 3102 cm^{2}$