Question

If CSA of cylinder is 616 cm²and the sum of radius and height is 21 cm then find TSA of cylinder??

Answer 1

Step-by-step explanation:

h+r=21......(1)

r=21-h

CSA=616 cm^2

2πrh=616cm^2

22/7×(21-h)h=616/2

22/7×21h-h^2=308

21h-h^2=308×7/22

21h-h^2=14×7

21h-h^2=98

h^2-21h+98=0

by solving the equation we get,

h=14.....(2)

putting (2) in (1)

r=7

TSA=2πr(h+r)

=2×(22/7)×(7)(21)

TSA=44×21=924cm^2

Answer 2

⠀⠀⠀⠀⠀${ \huge \bf{ \mid{ \overline{ \underline{ \pink{QUESTION}}}} \mid}} \longrightarrow</p><p>$

If CSA of cylinder is 616 cm²and the sum of radius and height is 21 cm then find TSA of cylinder??

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⠀⠀⠀⠀⠀⠀$\huge{ \underline{ \red{ \bold{ \underline{ \bf{AnSweR }}}}}}$

⠀⠀$\large\underline{ \underline{ \blue{ \bold {Given}}}} = >$

※CSA of cylinder = 616cm square.

※sum of radius and height

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⠀⠀$\large\underline{ \underline{ \blue{ \bold {To \:Find}}}} = >$

we have to find TSA of cylinder.

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⠀⠀⠀⠀⠀❖$\huge\underline{ \underline{ \purple{ \bold{solution}}}}$

⠀⠀⠀⠀⠀h + r = 21

⠀⠀⠀⠀ radius = 21 - h

we know that ,

⠀⠀⠀⠀⠀${\boxed{ \red{ \fbox{ \green{ \rm{CSA\: of \: cylinder = 2 \pi \: rh}}}}}}$

⠀⠀⠀so,

⠀⠀⠀⠀⠀2πrh = 616 cm square

$\bf \: \frac{22}{7} \times (21 - h)h = \frac{616}{2} \\ \\ = > \bf \frac{22}{7} \times 21h - h {}^{2} = 308 \\ \\ = > \bf \: h {}^{2} - 21h + 98=0$

⠀⠀⠀⠀⠀ solving equation

$\bf \: h {}^{2} - 21h + 98 = 0 \\ \\ \bf \: h(h - 7) - 14(h - 7) = 0 \\ \\ \bf \:( h - 7)(h - 14) \\ \\ \bf \: h = 14$

⠀⠀⠀⠀⠀we get h = 14

so,

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀r = 7

⠀⠀⠀${\boxed{ \red{ \fbox{ \green{ \rm{TSA \: of \: cylinder = 2 \pi \: r(h+r)}}}}}}$

$\bf2 \times \frac{22}{7} \times 7(14 + 7) \\ \\ \bf = > 44 \times 21 \\ \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \boxed{ \fbox{ \red{= > 924cm {}^{2} }}}$

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hops this may help you

⠀⠀⠀⠀⠀⠀⠀⠀$\huge{ \pink{ \ddot{ \smile}}}$

⠀⠀⠀⠀⠀⠀$\huge \mathfrak{ \blue { \bigstar{thanks}}}$