Pipe is that!

Geometry Level 3

An iron pipe 20 cm long has exterior diameter equal to 25 cm. If the thickness of the pipe is 1 cm, find the total surface area of the pipe. Write your answer in cm 2 \text{cm}^2 .
Note : Take π \pi as 22 7 \dfrac{22}{7} .


The answer is 3168.

View wiki
Anish Harsha by Anish Harsha , 20, India

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

2 solutions

Vignesh Rao
Feb 17, 2016

Let the external radius be R R and internal radius be r r

R = R = 25 2 = 12.5 cm \frac{25}{2} = 12.5 \text{ cm}

r = R − 1 = 12.5 − 1 = 11.5 cm r = R - 1 = 12.5-1 = 11.5 \text{ cm}

h = 20 cm h = 20 \text{ cm}

Total Surface Area of the pipe = 2 π ( R 2 − r 2 ) + 2 π h ( R + r ) \text{Total Surface Area of the pipe} = 2 \pi (R^2 - r^2)+2 \pi h (R+r)

⇒ 2 ∗ 22 7 ∗ 24 + 2 ∗ 22 7 ∗ 20 ∗ 24 \Rightarrow 2 * \frac{22}{7} * 24 + 2 * \frac{22}{7} * 20 * 24

2 ∗ 22 7 ∗ 24 ( 1 + 20 ) = 2 ∗ 22 7 ∗ 24 ∗ 21 = 3168 cm 2 2 * \frac{22}{7} * 24 (1 + 20) = 2 * \frac{22}{7} * 24 * 21 = \boxed{3168 \text{ cm}^2}

2 Helpful 0 Interesting 0 Brilliant 0 Confused

surface area=area of the base + lateral area = [ π 4 ( 2 5 2 − 2 3 2 ) ] ( 2 ) + π ( 20 ) ( 25 + 23 ) = \text{surface area=area of the base + lateral area}=\left[\dfrac{\pi}{4}(25^2-23^2)\right](2)+\pi(20)(25+23)= 3168 \boxed{3168}

1 Helpful 0 Interesting 0 Brilliant 0 Confused

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...