Question

9. Find the total surface area of a hollow cylinder open at both ends, if its length is 12 cm, external diamter is 8 cm and the thickness is 2 cm. ​

Answer 1

Step-by-step explanation:

Given that

Length l is 12cm

External diameter is 8cm

Thickness is 2cm

To find

Total surface area of hollow cylinder

Solution

Let r1 is the radius external

r is the inner radius

l is length

T is total surface area

$t = 2\pi \times l(r1 + r) + 2\pi( {r1}^{2} + {r}^{2} )$

$r1 = \frac{8}{2} = 4cm$

$r = \frac{4}{2} = 2cm$

hence

$t = 2\pi \times 12(4 + 2) + 2\pi( {4}^{2} + {2}^{2} )$

$t = 2 \times 22 \times 12$

$t = 528 {cm}^{2}$

hence total surface area of hollow cylinder is 528cm sq.

Answer 2

Answer:

582 sq cm

Step-by-step explanation:

Length l is 12cm

External diameter is 8cm

Thickness is 2cm

To find

Total surface area of hollow cylinder

Solution

Let r1 is the radius external

r is the inner radius

l is length

T is total surface area

t = 2\pi \times l(r1 + r) + 2\pi( {r1}^{2} + {r}^{2} )t=2π×l(r1+r)+2π(r1

2

+r

2

)

r1 = \frac{8}{2} = 4cmr1=

2

8

=4cm

r = \frac{4}{2} = 2cmr=

2

4

=2cm

hence

t = 2\pi \times 12(4 + 2) + 2\pi( {4}^{2} + {2}^{2} )t=2π×12(4+2)+2π(4

2+22)

t = 2 \times 22 \times 12t=2×22×12

t = 528 {cm}^{2}t=528cm

2