Question

The radius and height of a cone are in the ratio of 4:3. The area of the base is 154 sq.cm. Find the area of curved surface

Answer 1

We have given the ratio of radius and height 4 : 3
Say Radius = 4x
Height = 3x
Slant Height = root [(4x)2 +(3x)2 ]=5x { as it goes to Pythagorean Theorem}

as we know, Area of Base = pie X radius2 =>154=22/7 X 16x2

so solving the eq we get x=1.75cm

Radius=7 , Height =5.25cm, Slant Height =8.75cm

So csa or Curved Surface Area = pie X radius x slant height = 22/7 X 7 X 8.75 x=192.5cm2 (ans)