Question

An iron pipe 20 cm long has exterior diameter equal
to 25 cm. If the thickness of the pipe is 1 cm, find the
whole surface of the pipe.​

Answer 1

Answer:

Step-by-step explanation:

Hi, Here is the answer:

So the iron pipe here is a Hollow Cylinder

So the formulae for TOTAL SURFACE AREA OF THE PIPE:-

2$\pi$h(R + r) + 2$\pi$($R^{2} - r^{2}$)

Where,

R, radius of outer cylinder is = 25/2 = 12.5 cm

r, radius of inner cylinder is = 12.5 - 1 = 11.5 cm

h, height of the iron pipe is = 20 cm

SUBSTITUTING THE VALUES WE GET:

$2*22/7*20(12.5 + 11.5) + 2*22/7(12.5^{2} - 11.5^{2} )\\2*22/7 [20(24) +(24)]\\2*22/7 *504\\2*22*72\\44*72\\3168$

So the TOTAL SURFACE AREA OF THE PIPE IS : 3168 $cm^{2}$

HOPE THIS HELPS

Answer 2

GivEn:

• External diameter, D = 25 cm

• External radius, R = 12.5 cm

• Thickness of pipe = 1 cm

• Internal radius, r = (external radius - thickness) = 11.5 cm

• Height of the pipe, h = 20 cm

To find:

• Total surface area of the pipe.

SoluTion:

Total surface area of the pipe,

= (External CSA) + (Internal CSA) + 2(Area of base)

$:\implies\sf 2 \pi Rh + 2 \pi rh + 2(\pi R^2 - \pi r^2)$

$:\implies\sf 2 \pi(R + r)h + 2 \pi(R^2 - r^2)$

$:\implies\sf 2 \pi(R + r)h + 2 \pi(R + r)(R - r)$

$:\implies\sf 2 \pi(R + r)(h + R - r)$

⠀⠀⠀━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Now, Putting values,

$:\implies\sf 2 \times \dfrac{22}{7} \times (12.5 + 11.5) \times (20 + 12.5 - 11.5)$

$:\implies\sf 2 \times \dfrac{22}{7} \times 24 \times 21$

$:\implies{\boxed{\frak{\purple{3168\;cm^2}}}}\;\bigstar$

$\therefore\;{\underline{\sf{Hence,\;TSA\;of\;pipe\;is\; \bf{3168\;cm^2}.}}}$

⠀⠀⠀━━━━━━━━━━━━━━━━━━━━━━━━━━━━

$\qquad\qquad\boxed{\bf{\mid{\overline{\underline{\pink{\bigstar\: More\:to\:know :}}}}}\mid}$

$\;\;\;\bullet\;\;\sf CSA\;of\;Cylinder = 2 \pi rh$

$\;\;\;\bullet\;\;\sf TSA\;of\;Cylinder = 2 \pi r(h + r)$

$\;\;\;\bullet\;\;\sf Volume\;of\;Cylinder = \dfrac{1}{3} \pi r^2 h$