The radius and slant height of a cone are in the ratio of 4:7. If its curved surface area is `792\ c m^2,` find the radius. `(U s e\ pi=(22)/7)`

Explanation

let radius of cone`=4x`

slant height `l=7x`

according to question,

`pirl=792cm^2`

`(22/7)xx(4x)xx(7x)=792`

`x=3`

so radius `r=4xx3=12cm`