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

Volume of rice = volume of cone = 1/3πr²h
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 = √(r² + h²)
= √{12² + 3.5²} = √{144 + 12.25 } = √{156.25} = 12.5 m
∴ area of canvas cloth = 22/7 × 12 × 12.5 m²
= 471.42 m²

Answer 2

Solution :-

Base diameter of cone = 24 m

Radius = 24/2 = 12 m

Height = 3.5 m

Volume of cone = 1/3*πr²h

⇒ 1/3*22/7*12*12*3.5

⇒ 11088/21

Volume of cone = 528 m³

Slant height 'l' = √h² + r²

⇒ √3.5² + 12²

⇒ √12.25 + 144

⇒ √156.25

⇒ l =  12.5 m

Curved surface area of cone = πrl

⇒ 22/7*12*12.5

⇒ 3300/7

⇒ 471.428 m²

 Area of canvas cloth required to cover the rice is 471.428 m²

Answer.