Question

The radii of the ends of a bucket 30 cm high are 21 cm and 7 cm. Find its capacity in litres and the amount of sheet required to make this bucket.

Answer 1

Although we can solve this problem by suing the similar trianlges, but here we are using the direct formula.
Volume of bucket=`(1)/(3)pih(r_(1^(2))+r_(1)r_(2)+r_(2^(2))`
`=(1)/(3)xx(22)/(7)xx30(21^(2)+21xx7+7^(2))`
`=(1)/(3)xx(22)/(7)xx30x637=20020 cm^(3)=(20020)/(1000)lit`
Capacity =20.2 lit
Area of sheeet = C.S.A of bucket +Area of bse
,=`pil(r_(1)+r_(2))+pir_(2)^(2)=pi[l(r_(1)+r_(2))+r_(2)^(2))]`
`=(22)/(7)[33.10^(28)+49]`
3067.32=3067 `cm^(2)` (approx)