The radius of the base of a cylindrical water-drum open at the top at the top is 35 cm and height 1.3m. Find the inner surface area of the water-drum.

Explanation

Radius of water-drum `r=35 cm`
Height of water-drum `h=1.3 m=130 cm`
Inner surface area of water-drum`=`Curved surface area + Area of base
`=2pirh+pir^2`
`=pir(2h+r)`
`=22/7times35times(2times130+35)cm^2`
`=22times5times295cm^2`
`=32450cm^2`