Question

Q10. The radius of the base and the height of a solid right circular cylinder are in the ratio2:3 and its volume are 1617. Cm 3 . find the total surface area of the cylinder. {Use π=22/7 }

Answer 1

volume of cylinder=pi.r^2.h

question given,

r:h=2:3

let proportionality constant y
r=2y/5 cm
h=3y/5 cm

now
volume of cylinder=pi.r^2.h

1617=22/7 x (2y/5)^2 x (3y/5)

1617=22/7 x 12y^3/125

y=35/2
now radius (r) =2/5 x 35/2=7cm
and height (h)=3/5x35/2=10.5cm

now surface area of cylinder=2pi.r.h
=2 x 22/7 x 7 x (10.5)
=462 cm^2