Question

the radius and height of a cone are in the ratio 4 is to 3 the area of the base is 154 cm square find the area of the curved surface

Answer 1

$\frac{r}{h} = \frac{4}{3}$
base area = 2πr^2=154
csa = 2πrh
$154 = 2\pi {r}^{2}$
2πr^2=154
πr^2=154/2
r^2=77/π .........(i)
r/h=4/3
h=3r/4
csa=2πr×3r/4
=πr^2/4 .........(ii)
put the value of r^2 in eq. (ii)
77/π×π/4
77/4
csa=19.25cm^2

Answer 2

r/h=4/3

radius=4x
height=3x

base area=154
Area of Base = pie X radius2 =>154=22/7 X 16x2 
x=1.75cm 

r=7cm , Height =5.25cm, Slant Height =8.75cm 
Curved Surface Area = pie X radius x slant height = 22/7 X 7 X 8.75 x=192.5cm2