`127(2)/(7)` sq. cm of sheet is required to make a hemispherical bowl. Calculate the length of diameter of the forepart of the bowl.

Explanation

Let the radius of the forepart of the bowl be r cm .
`therefore` the quantity of sheet required to make the bowl `=2pir^(2)` sq.cm.
As per question `2pir^(2)=172(2)/(7)rArr 2xx(22)/(7)xxr^(2)=(891)/(7)rArr r^(2)=(891xx7)/(7xx2xx22)rArrr^(2)=(81)/(4) rArr r=(9)/(2).`
So, the diameter of ot the bowl =`2xx(9)/(2)`cm=9 cm.