Q8 of 32 Page 250

A heap of rice is in the form of a cone of diameter 12 m. and height 8 m. Find its volume? How much canvas cloth is required to cover the heap?

(use π = 3.14)


Given that, the diameter(d) of cone is 12 cm and heigh(h)t is 8 cm.


⇒ radius(r)


And, Surface area of cone is - πrl


Also, volume of cone


Also, slant height(l) = √ r2 + h2


⇒ l = √ 62 + 82


⇒ l = √ 36 + 64


⇒ l = √ 100


⇒ l = 10


⇒ volume of heap



= 301.44 cm3


⇒ Surface area of cone = 3.14 × 6 × 10


= 188.4 cm2


⇒ ∴ canvas cloth required to cover the heap = 188.4 cm2


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