Question

a heap of rice in the form of cone of base diameter 24m and height 3.5m find the volume of the rice how much canvas cloth is required to just cover the heap

Answer 1

Did you look up to the Leaked question paper of maths ?? because you posted this question a day before Maths cbse class 10 exam
anyways,

Volume = 1/3πr2h
1/3 × 22/7 × 12×12×3.5
= 528 m3

Canvas of cloth required = CSA Of cone
l = √144+12.25
=25/2=12.5m

CSA = 3.14×12×12.5
=471 m2

Answer 2

Volume of rice = volume of cone = $\frac{1}{3}\pi r^2h$
Here , r = 12 [ ∵ diameter = 24 m ] and h = 3.5m

Now, volume of rice = 1/3 × 22/7 × (12)² × 3.5 m³
= 1/3 × 22/7 × 12 × 12 × 7/2 m³
=22 × 24 = 528 m³

Again, area of canvas cloth = curve surface area of cone = πrl
Here l = $\sqrt{r^2+h^2}$
= √{12² + 3.5²} = √{144 + 12.25 } = √{156.25} = 12.5 m
∴ area of canvas cloth = 22/7 × 12 × 12.5 m²
= 471.42 m²