Question

The area of the base of a conical solid is 38•5cm² and its volume is 154cm³.Find curved surface area of the solid.

Answer 1

base area of conical solid =pi.r^2
38.5 cm^2=22/7 xr^2
77/2 cm^2=22/7 x r^2
r^2 =49/4
r=7/2 cm

again
volume of conical solid =pi.r^2.h/3
154 cm^3= 22/7 x 49/4 x h/3
h=12 cm

now
curve surface area of conical solid=pi.r.l
but l is slant height
l=root {(7/2)^2+(12)^2}
=root {156.25}=12.5cm
now
curve surface area=22/7 x 7/2 x (12.5)
=137.5 cm^2