Question

the sum and difference of the outer and innee radii of a hollow cylinder are 5cm and 2 cm respectively.If the height of the cylinder is 1.4 cm,find its (a)curved surface area (b) total surface area (c)volume​

Answer 1

Answer:

Answer

Let r,R and h be the internal, external radii and the height of a hollow cylinder respectively.

Given that r=12cm, R=18cm, h=14cm

Now, curved surface area, CSA=2πh(R+r)

Thus, CSA=2×

7

22

×14×(18+12)

=2640sq.cm

Total surface area, TSA=2π(R+r)(R−e+h)

=2×

7

22

×(18+12)(18−12+14)

=2×

7

22

×30×20=

7

26400

Thus, the total surface area =3771

7

3

sq.cm