Question

A heap of rice is in the form of cone of diameter 9 m and height 3 .5 m Find the volume of the rice. How much canvas cloth is required to just cover the heap

Answer 1

Volume of cone = 1/3 * pie * r * r * h

D = 9 m , r = 9 / 2 m

Volume = (1 / 3) * (22 / 7) * (9/2)*(9/2)*(3.5) = 74.25 m3

Just to cover , the heap, we need the CSAof cone

Slant height of cone = root [ r2 + h2 ] = root [ (9 / 2) * (9 / 2) + (3.5)*(3.5) ] = 5.7008 m

CSA= pie * r * l = (22 / 7) * (9/2) * (5.7008) = 80.6256 m

Cheers!

Best of Luck!

Answer 2

hello users ...
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Given that:
diameter of the base of cone = 9 m 
and
height of cone = 3.5 m

we have to find:
(1.) volume of cone 
(2.) cloth required to just cover the heap ( C.S.area of cone ).

solution:-
we know that 
volume of cone = 1/3 ×π×r²×h
and
curved surface area of cone = π×r×l
and
slant height (l) = √(h² + r²)
Here,
According to given :
diameter of the base of cone = 9 m 
=> radius of base of cone = 9/2 = 4.5 m 

now,
volume of cone = 1/3× π×r²×h
= 1/3×22/7×(4.5)²× 3.5

= 22/21 ×20.25 ×3.5

= 1559.25 / 21 = 74.25 m³ Answer 

and,
Slant height (l) = √(h² +r²)
= √(3.5² + 4.5²)
= √(12.25 + 20.25)
=√32.5 = 5.7 m

Now,
the cloth required to cover this heap = C.S. area 
= π×r×l

= 22/7× 4.5×5.7 

= 80.61428 m²

≈80.62 m² Answer 
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# hope it helps :)