If the ratio of the curved surface area and volume of right circular cylinder is 5 : 7, then its radius is:

2.8 unit

We know that,

Curved surface area of cylinder = 2πrh 

Volume of the cylinder = πr²h

Ratio of the curved surface area and volume of a right circular cylinder =  5 ∶ 7

\(\frac{2πrh}{ πr^2h}\) = \(\frac{5}{7}\)

= \(\frac{2}{r}\)= \(\frac{5}{7}\)

= \(\frac{2}{r}\)= \(\frac{5}{7}\)

= r = \(\frac{14}{5}\)= 2.8 units