Question

The ratio of radius and height of a cylinder is 2:3. The total surface area of the base is 98.56 cm². Find the CSA ????​

Answer 1

Answer:

Given, ratio of radius and height of cone is 4:3:.

Then, let radius be 4x and height be 3x.

We know, the base of a cone is a circle.

∴ Area of base = πr

2

=154⇒

7

22

×(4x)

2

=154

⇒16x

2

=

22

154×7

⇒x

2

=

16

49

⇒x=

4

7

.

∴ Radius = 4×

4

7

=7cm, and height =3×

4

7

=

4

21

=5.25cm.

Now, curved surface area of cone = πrl and l=

r

2

+h

2

=

49+(5.25)

2

=8.75cm.

∴ Curved surface area =

7

22

×7×8.75=192.5cm

2

.