Math, asked by insha34, 1 year ago

ans correctly plzzzzzzzzzzzzzzzz​

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Answers

Answered by HariTheGreat
1

TSA of cylinder = 231

i.e 2πr(r+h) = 231 - (1)

According to the condition given in the question,

CSA of cylinder = 2/3 TSA of cylinder

2πrh = 2/3 πr(r+h)

(2πr is cancelled)

h = 2/3 (r+h)

3h = 2r+2h

h = 2r

by substituting h = 2r in (1)

2×22/7×r(r+2r) = 231

44/7× 3r^2 = 231

r = 7/2

Hope it help you ;)


HariTheGreat: was it helpful for you
insha34: yes its very helpful
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HariTheGreat: any clarification needed
harjotsinghbhinder13: nice attempt hari but your answer is wrong
HariTheGreat: read the question carefully it is asked to find the radius of base and 7/2 is 3.5 itself
insha34: yes your ans is right
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Answered by harjotsinghbhinder13
1

Hello mate,

Here is your answer

the total surface area of cylinder =231cm2

=> 2πr(r+h)=231 cm2

=> 2πr2+2πrh=231 cm2--------(a)

its curved surface area is=2/3(231)cm2 (given)

=> 2πrh=154 cm2 --------(b)

putting value of 2πrh from equ. (b) in equ. (a) we get

=> 2πr2+154=231

=>2πr2=231-154

=>2πr2=77

=>r2=77/(2π)

=> r2=12.25 (since π=22/7)

=> r=(12.25)1/2 cm = 3.5 cm

to find the value of h

now by putting the value of r=3.5cm in equ. (b) we get

=> 2πrh=154

=> 2(22/7)*3.5* h=154

=> 22h=154

=> h=154/22 cm = 7cm

pls Mark it as BRAINLIEST!!!!

Thanks!!!!


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